Bump git2 from 0.13.18 to 0.13.19 (#422)

Bumps [git2](https://github.com/rust-lang/git2-rs) from 0.13.18 to 0.13.19.
- [Release notes](https://github.com/rust-lang/git2-rs/releases)
- [Commits](rust-lang/git2-rs@0.13.18...0.13.19)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Cargo.lock

@@ -29,7 +29,7 @@ clap = "2.33.3"
 color_quant = "1.1.0"
 colored = "2.0.0"
 error-chain = "0.12"
-git2 = {version = "0.13.18", default-features = false}
+git2 = {version = "0.13.19", default-features = false}
 image = "0.23.14"
 json = "0.12.4"
 regex = "1.4.6"