build(deps): bump rustversion from 1.0.20 to 1.0.21 (#3931)

Bumps [rustversion](https://github.com/dtolnay/rustversion) from 1.0.20 to 1.0.21.
- [Release notes](https://github.com/dtolnay/rustversion/releases)
- [Commits](dtolnay/rustversion@1.0.20...1.0.21)

---
updated-dependencies:
- dependency-name: rustversion
  dependency-version: 1.0.21
  dependency-type: indirect
  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>

Author: dependabot[bot]

Cargo.lock

@@ -3793,9 +3793,9 @@ dependencies = [
 
 [[package]]
 name = "rustversion"
-version = "1.0.20"
+version = "1.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eded382c5f5f786b989652c49544c4877d9f015cc22e145a5ea8ea66c2921cd2"
+checksum = "8a0d197bd2c9dc6e53b84da9556a69ba4cdfab8619eb41a8bd1cc2027a0f6b1d"
 
 [[package]]
 name = "ryu"