build(deps): bump git2 from 0.20.3 to 0.20.4

Bumps [git2](https://github.com/rust-lang/git2-rs) from 0.20.3 to 0.20.4.
- [Changelog](https://github.com/rust-lang/git2-rs/blob/git2-0.20.4/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/git2-rs/compare/git2-0.20.3...git2-0.20.4)

---
updated-dependencies:
- dependency-name: git2
  dependency-version: 0.20.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Cargo.lock

@@ -658,9 +658,9 @@ dependencies = [
 
 [[package]]
 name = "git2"
-version = "0.20.3"
+version = "0.20.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3e2b37e2f62729cdada11f0e6b3b6fe383c69c29fc619e391223e12856af308c"
+checksum = "7b88256088d75a56f8ecfa070513a775dd9107f6530ef14919dac831af9cfe2b"
 dependencies = [
  "bitflags",
  "libc",