Upgrade git2 dependency (#217)

To date, the latest git2-ext release is not compatible with latest git2,
so for the time being we must depend on a PR that fixes that.

Author: spacedentist

Cargo.lock

@@ -15,8 +15,8 @@ console = "^0.15.11"
 dialoguer = "^0.10.4"
 futures = "^0.3.31"
 futures-lite = "^1.13.0"
-git2 = { version = "^0.17.2", default-features = false }
-git2-ext = "0.6.2"
+git2 = { version = "^0.20.1", default-features = false }
+git2-ext ={ git="https://github.com/mhammerly/git2-ext.git", rev = "115a912b7b89d91c03d1e52e0d39b60adb04dde6" }
 graphql_client = "^0.11.0"
 indoc = "^1.0.9"
 lazy-regex = "^2.5.0"