Bump serde_yaml from 0.9.19 to 0.9.21 (#416)

Bumps [serde_yaml](https://github.com/dtolnay/serde-yaml) from 0.9.19 to 0.9.21.
- [Release notes](https://github.com/dtolnay/serde-yaml/releases)
- [Commits](https://github.com/dtolnay/serde-yaml/compare/0.9.19...0.9.21)

---
updated-dependencies:
- dependency-name: serde_yaml
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.lock

@@ -1666,9 +1666,9 @@ dependencies = [
 
 [[package]]
 name = "serde_yaml"
-version = "0.9.19"
+version = "0.9.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f82e6c8c047aa50a7328632d067bcae6ef38772a79e28daf32f735e0e4f3dd10"
+checksum = "d9d684e3ec7de3bf5466b32bd75303ac16f0736426e5a4e0d6e489559ce1249c"
 dependencies = [
  "indexmap",
  "itoa",