Bump serde_yaml from 0.9.17 to 0.9.21

Bumps [serde_yaml](https://github.com/dtolnay/serde-yaml) from 0.9.17 to 0.9.21.
- [Release notes](https://github.com/dtolnay/serde-yaml/releases)
- [Commits](https://github.com/dtolnay/serde-yaml/compare/0.9.17...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>

Cargo.lock

@@ -1125,9 +1125,9 @@ dependencies = [
 
 [[package]]
 name = "serde_yaml"
-version = "0.9.17"
+version = "0.9.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8fb06d4b6cdaef0e0c51fa881acb721bed3c924cfaa71d9c94a3b771dfdf6567"
+checksum = "d9d684e3ec7de3bf5466b32bd75303ac16f0736426e5a4e0d6e489559ce1249c"
 dependencies = [
  "indexmap",
  "itoa",
@@ -1347,9 +1347,9 @@ checksum = "5bd2fe26506023ed7b5e1e315add59d6f584c621d037f9368fea9cfb988f368c"
 
 [[package]]
 name = "unsafe-libyaml"
-version = "0.2.4"
+version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1e5fa573d8ac5f1a856f8d7be41d390ee973daf97c806b2c1a465e4e1406e68"
+checksum = "1865806a559042e51ab5414598446a5871b561d21b6764f2eabb0dd481d880a6"
 
 [[package]]
 name = "version_check"