Bump git2 from 0.13.20 to 0.16.1

Bumps [git2](https://github.com/rust-lang/git2-rs) from 0.13.20 to 0.16.1.
- [Release notes](https://github.com/rust-lang/git2-rs/releases)
- [Commits](rust-lang/git2-rs@0.13.20...0.16.1)

---
updated-dependencies:
- dependency-name: git2
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.lock

@@ -5,7 +5,7 @@ authors = ["The Rust Project Developers"]
 edition = "2018"
 
 [dependencies]
-git2 = "0.13"
+git2 = "0.16"
 serde = { version = "1", features = ["derive"] }
 semver = "1"
 tempfile = "3"