fix(deps): update rust crate git2 to 0.21 (#132)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Cargo.toml

@@ -8,7 +8,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 chrono = "0.4"
-git2 = { version = "0.20", features = ["default", "vendored-libgit2", "vendored-openssl"] }
+git2 = { version = "0.21", features = ["default", "vendored-libgit2", "vendored-openssl"] }
 libgit2-sys = { version = "*", features = ["ssh", "https", "vendored", "vendored-openssl"] }
 home = "0.5"
 once_cell = "1"