Bump proc-macro2 from 1.0.80 to 1.0.81 (#785)

Bumps [proc-macro2](https://github.com/dtolnay/proc-macro2) from 1.0.80 to 1.0.81.
- [Release notes](https://github.com/dtolnay/proc-macro2/releases)
- [Commits](https://github.com/dtolnay/proc-macro2/compare/1.0.80...1.0.81)

---
updated-dependencies:
- dependency-name: proc-macro2
  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

@@ -1386,9 +1386,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.80"
+version = "1.0.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a56dea16b0a29e94408b9aa5e2940a4eedbd128a1ba20e8f7ae60fd3d465af0e"
+checksum = "3d1597b0c024618f09a9c3b8655b7e430397a36d23fdafec26d6965e9eec3eba"
 dependencies = [
  "unicode-ident",
 ]