[git] Migrate git method from Ruby to Python (#178)

The main reason for doing this is to have some common code between scripts, so that it is easier to change the JSON schema globally and normalize a few things (such as release order).

The Ruby code was kept as is so we can quickly roll back if necessary.

src/debian.py

@@ -51,11 +51,11 @@ def extract_point_releases(releases, repo_dir):
             print(f"{version}: {date}")
             releases[version] = date
 
+print(f"::group::{PRODUCT}")
 git = Git(REPO_URL)
 git.setup()
 git.checkout("master", file_list=["english/News"])
 
-print(f"::group::{PRODUCT}")
 all_releases = {}
 extract_major_releases(all_releases, git.repo_dir)
 extract_point_releases(all_releases, git.repo_dir)