Auto merge of #6959 - rust-lang:dependabot/cargo/im-rc-13.0.0, r=alexcrichton

Update im-rc requirement from 12.1.0 to 13.0.0

Updates the requirements on [im-rc](https://github.com/bodil/im-rs) to permit the latest version.
<details>
<summary>Release notes</summary>

*Sourced from [im-rc's releases](https://github.com/bodil/im-rs/releases).*

> ## 13.0.0
> The minimum supported Rust version is now 1.34.0.
>
> ### Changed
>
> - `im::iter::unfold` now gives you the owned state value rather than an immutable reference to it, which makes it a little more useful.
>
> ### Removed
>
> - The deprecated `singleton` constructors have been removed. Please use `unit` instead.
> - The deprecated methods `Vector::chunks` and `Vector::chunks_mut` have been removed in favour of `Vector::leaves` and `Vector::leaves_mut` respectively. ([#50](https://github-redirect.dependabot.com/bodil/im-rs/issues/50))
> - The deprecated reference to [`sized-chunks`](https://crates.io/crates/sized-chunks) has been removed. If you need it, please use the `sized-chunks` crate directly.
> - `im::iter::unfold_mut` has been removed, as there's no meaningful difference between it and rust-std 1.34.0's `std::iter::from_fn` with a captured state variable.
>
> ### Fixed
>
> - `Vector` now uses [`sized_chunks::InlineArray`](https://docs.rs/sized-chunks/0.3.0/sized_chunks/inline_array/struct.InlineArray.html) instead of an `Empty` enum case to avoid allocation at very small sizes, letting you store a handful of elements on the stack before needing to grow into a full chunk. This has a beneficial effect on performance as well, as there's no pointer into the heap to dereference, making it faster than `std::vec::Vec` in this configuration.
> - Some complexity timings have been added and corrected. ([#87](https://github-redirect.dependabot.com/bodil/im-rs/issues/87))
> - `OrdSet::is_subset(&self, other)` now returns immediately when `self` is larger than `other` and thus could not possibly be a subset of it. ([#87](https://github-redirect.dependabot.com/bodil/im-rs/issues/87))
</details>
<details>
<summary>Changelog</summary>

*Sourced from [im-rc's changelog](https://github.com/bodil/im-rs/blob/master/CHANGELOG.md).*

> ## [13.0.0] - 2019-05-18
>
> The minimum supported Rust version is now 1.34.0.
>
> ### Changed
>
> - `im::iter::unfold` now gives you the owned state value rather than an
>   immutable reference to it, which makes it a little more useful.
>
> ### Removed
>
> - The deprecated `singleton` constructors have been removed. Please use `unit`
>   instead.
> - The deprecated methods `Vector::chunks` and `Vector::chunks_mut` have been
>   removed in favour of `Vector::leaves` and `Vector::leaves_mut` respectively.
>   ([#50](https://github-redirect.dependabot.com/bodil/im-rs/issues/50))
> - The deprecated reference to [`sized-chunks`](https://crates.io/crates/sized-chunks)
>   has been removed. If you need it, please use the `sized-chunks` crate directly.
> - `im::iter::unfold_mut` has been removed, as there's no meaningful difference
>   between it and rust-std 1.34.0's `std::iter::from_fn` with a captured state
>   variable.
>
> ### Fixed
>
> - `Vector` now uses
>   [`sized_chunks::InlineArray`](https://docs.rs/sized-chunks/0.3.0/sized_chunks/inline_array/struct.InlineArray.html)
>   instead of an `Empty` enum case to avoid allocation at very small sizes,
>   letting you store a handful of elements on the stack before needing to grow
>   into a full chunk. This has a beneficial effect on performance as well, as
>   there's no pointer into the heap to dereference, making it faster than
>   `std::vec::Vec` in this configuration.
> - Some complexity timings have been added and corrected. ([#87](https://github-redirect.dependabot.com/bodil/im-rs/issues/87))
> - `OrdSet::is_subset(&self, other)` now returns immediately when `self` is
>   larger than `other` and thus could not possibly be a subset of it. ([#87](https://github-redirect.dependabot.com/bodil/im-rs/issues/87))
>
> ## [12.3.4] - 2019-04-08
>
> ### Changed
>
> - `Clone` constraints have been further relaxed on maps and sets, so that you
>   can now lookup and iterate over them without requiring a `Clone` constraint
>   (though you do still need `Clone` to actually insert data into them to lookup
>   or iterate over). ([#81](https://github-redirect.dependabot.com/bodil/im-rs/issues/81))
>
> ### Fixed
>
> - Enforces the latest bugfix release of sized-chunks. ([#78](https://github-redirect.dependabot.com/bodil/im-rs/issues/78))
> - Another edge case bugfix to `Vector`'s size table handling. ([#79](https://github-redirect.dependabot.com/bodil/im-rs/issues/79))
>
> ## [12.3.3] - 2019-03-11
></tr></table> ... (truncated)
</details>
<details>
<summary>Commits</summary>

- [`1e59b66`](bodil/im-rs@1e59b66) (cargo-release) version 13.0.0
- [`6ddf406`](bodil/im-rs@6ddf406) Broken link fix.
- [`60de96d`](bodil/im-rs@60de96d) Replace `Vector::Empty` with `Vector::Inline` using `InlineArray`.
- [`b7578f8`](bodil/im-rs@b7578f8) Fix Vector benchmark from_fn issues.
- [`d2befa1`](bodil/im-rs@d2befa1) Merge pull request [#89](https://github-redirect.dependabot.com/bodil/im-rs/issues/89) from AljoschaMeyer/master
- [`f519c66`](bodil/im-rs@f519c66) Adjust doc tests
- [`37f8046`](bodil/im-rs@37f8046) Add relative_complement to sets/maps
- [`01f2726`](bodil/im-rs@01f2726) Add symmetrical_difference to sets/maps
- [`c0a8fc6`](bodil/im-rs@c0a8fc6) Add timings to more `OrdSet` ops, and an early return optimisation to `is_sub...
- [`7c5f501`](bodil/im-rs@7c5f501) Merge pull request [#84](https://github-redirect.dependabot.com/bodil/im-rs/issues/84) from bodil/dependabot/cargo/sized-chunks-0.2.0
- Additional commits viewable in [compare view](bodil/im-rs@12.1.0...13.0.0)
</details>
<br />

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot squash and merge` will squash and merge this PR after your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge and block automerging
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot ignore this [patch|minor|major] version` will close this PR and stop Dependabot creating any more for this minor/major version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)
- `@dependabot use these labels` will set the current labels as the default for future PRs for this repo and language
- `@dependabot use these reviewers` will set the current reviewers as the default for future PRs for this repo and language
- `@dependabot use these assignees` will set the current assignees as the default for future PRs for this repo and language
- `@dependabot use this milestone` will set the current milestone as the default for future PRs for this repo and language
- `@dependabot badge me` will comment on this PR with code to add a "Dependabot enabled" badge to your readme

Additionally, you can set the following in your Dependabot [dashboard](https://app.dependabot.com):
- Update frequency (including time of day and day of week)
- Automerge options (never/patch/minor, and dev/runtime dependencies)
- Pull request limits (per update run and/or open at any time)
- Out-of-range updates (receive only lockfile updates, if desired)
- Security updates (receive only security updates, if desired)

Finally, you can contact us by mentioning @dependabot.

</details>

Author: bors

Cargo.toml

@@ -64,7 +64,7 @@ walkdir = "2.2"
 clap = "2.31.2"
 unicode-width = "0.1.5"
 openssl = { version = '0.10.11', optional = true }
-im-rc = "12.1.0"
+im-rc = "13.0.0"
 
 # A noop dependency that changes in the Rust repository, it's a bit of a hack.
 # See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`