build(deps): bump nix from 0.20.0 to 0.20.2

Bumps [nix](https://github.com/nix-rust/nix) from 0.20.0 to 0.20.2.
- [Release notes](https://github.com/nix-rust/nix/releases)
- [Changelog](https://github.com/nix-rust/nix/blob/v0.20.2/CHANGELOG.md)
- [Commits](nix-rust/nix@v0.20.0...v0.20.2)

---
updated-dependencies:
- dependency-name: nix
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.lock

@@ -27,7 +27,7 @@ hyper = "0.14.4"
 itertools = "0.10.0"
 lazy_static = "1.4.0"
 log = "0.4.14"
-nix = "0.20.0"
+nix = "0.20.2"
 num_enum = "0.5.1"
 orchestra = { git = "https://github.com/fluidex/orchestra.git", branch = "master", features = [ "exchange" ] }
 paperclip = { git = "https://github.com/fluidex/paperclip.git", features = [ "actix", "chrono", "rust_decimal" ] }