chore(deps): bump git2 from 0.20.4 to 0.21.0 in /bots/finishingbot

Bumps [git2](https://github.com/rust-lang/git2-rs) from 0.20.4 to 0.21.0.
- [Changelog](https://github.com/rust-lang/git2-rs/blob/main/CHANGELOG.md)
- [Commits](rust-lang/git2-rs@git2-0.20.4...git2-0.21.0)

---
updated-dependencies:
- dependency-name: git2
  dependency-version: 0.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

bots/finishingbot/Cargo.lock

@@ -35,7 +35,7 @@ tracing-subscriber = { version = "0.3", features = ["env-filter", "json"] }
 tracing-appender = "0.2"
 
 # Git operations
-git2 = "0.20"
+git2 = "0.21"
 
 # HTTP client (for license verification)
 reqwest = { version = "0.12", features = ["json", "rustls-tls"], default-features = false }