Update Rust crate git2 to v0.20.0 (#10315)

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

Author: renovate[bot]

Cargo.lock

@@ -19,7 +19,7 @@ testing = []
 anyhow = "=1.0.95"
 base64 = "=0.22.1"
 crates_io_env_vars = { path = "../crates_io_env_vars" }
-git2 = "=0.19.0"
+git2 = "=0.20.0"
 secrecy = "=0.10.3"
 serde = { version = "=1.0.217", features = ["derive"] }
 serde_json = "=1.0.134"