Add --no-dev-dependencies to generate-lockfile

[jyn514]

Describe the problem you are trying to solve

In some cases, crates may have cyclic dependencies if you count dev-dependencies, but work fine without. For example, the proc-macro https://crates.io/crates/zbus_macros 1.0.0 has a dev-dependency on https://crates.io/crates/zbus 1.0.0, which in turn has a normal dependency on zbus_macros. When docs.rs tried to generate the lockfile for zbus_macros, it got an error because zbus had not yet been published:

Command { std: "/home/cratesfyi/workspace/cargo-home/bin/cargo" "+nightly" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
    Updating crates.io index
error: failed to select a version for the requirement `zbus = "^1"`
candidate versions found which didn't match: 0.1.2
location searched: crates.io index

Describe the solution you'd like

docs.rs doesn't actually need the dev-dependencies to run cargo doc. If we could use generate-lockfile --no-dev-dependencies that should fix the issues here. I have no idea how hard that would be for cargo though.

Notes

[ehuss]

Hm, I'm a bit surprised that crates.io allows publishing with a version that does not exist. In a way, this isn't specific to dev-dependencies, as you could have any normal dependency pointing to a version that has not yet been published. Though I guess it is more likely to hit dev-dependencies because otherwise you need to publish with --no-verify.

Anyways, this already exists as -Zavoid-dev-deps (#5133).

[ehuss]

Closing as the avoid-dev-deps is already implemented. However, for the root issue where docs.rs has issues with yet-to-be-published dependencies, that seems to be a broader problem with atomically publishing multiple crates at once (tracked in #1169 and rust-lang/crates-io-cargo-teams#82).