DAG-Bundle : Git connections ignore credentials for public repositories, causing anonymous rate limit issues

Hi everyone, ### Description I recently came across the problem, that the git-fetch-requests of the dag-bundle hit the rate-limit of the git-server. I found out that Airflow cannot **take advantage of a higher rate-limit for authorized git-requests** if the repo is public as it never sends the credentials to the server. But Airflow could support to **force authentication** for a git connection type via a custom http.extraHeader as additional argument to the git command. This would allow authenticated Git operations even for public repositories. ### Use case/motivation Git does not authenticate when syncing public repositories, even if login and password are set. This is due to Git’s HTTPS behavior: **it always tries anonymous access first** and only sends credentials if the server responds with a 401 Unauthorized. => Public repos typically do not issue a 401, so credentials are never used. This is problematic because GitLab/GitHub apply different rate limits for authenticated vs anonymous requests. As a result, Airflow tasks can hit anonymous rate limits even when valid credentials are provided. **A known workaround** is to use Git’s http.extraHeader option to force authentication: ``` B64=$(printf 'x:%s' "<PROJECT_ACCESS_TOKEN>" | base64) git -c http.extraHeader="Authorization: Basic $B64" clone https://gitlab.com/<group>/<repo>.git ``` This ensures that all requests are authenticated from the first request, avoiding anonymous rate limits. ### Related issues _No response_ ### Are you willing to submit a PR? - [ ] Yes I am willing to submit a PR! - [x] I am still thinking about a possible solution ... This functionality probably could be added here 🤔 https://github.com/apache/airflow/blob/main/providers/git/src/airflow/providers/git/hooks/git.py Perhaps by additional extra arguments - `config-env` : which represents the git argument `--config-env` - https://git-scm.com/docs/git/2.34.0#Documentation/git.txt---config-envnameenvvar - `env` : which allows to extent th…