build: bump git2 from 0.13.20 to 0.13.21 (#2983)

Bumps [git2](https://github.com/rust-lang/git2-rs) from 0.13.20 to 0.13.21.
- [Release notes](https://github.com/rust-lang/git2-rs/releases)
- [Commits](https://github.com/rust-lang/git2-rs/compare/0.13.20...0.13.21)

---
updated-dependencies:
- dependency-name: git2
  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

@@ -684,9 +684,9 @@ dependencies = [
 
 [[package]]
 name = "git2"
-version = "0.13.20"
+version = "0.13.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9831e983241f8c5591ed53f17d874833e2fa82cac2625f3888c50cbfe136cba"
+checksum = "659cd14835e75b64d9dba5b660463506763cf0aa6cb640aeeb0e98d841093490"
 dependencies = [
  "bitflags 1.2.1",
  "libc",
@@ -818,9 +818,9 @@ checksum = "320cfe77175da3a483efed4bc0adc1968ca050b098ce4f2f1c13a56626128790"
 
 [[package]]
 name = "libgit2-sys"
-version = "0.12.21+1.1.0"
+version = "0.12.22+1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86271bacd72b2b9e854c3dcfb82efd538f15f870e4c11af66900effb462f6825"
+checksum = "89c53ac117c44f7042ad8d8f5681378dfbc6010e49ec2c0d1f11dfedc7a4a1c3"
 dependencies = [
  "cc",
  "libc",