* Disable git safe repo check and optimize behavior

List of changes:

- Add global config option to make our clone directory "safe". Without
  this, the github action fails completely due to some security features
  implemented in the newest version of git.
- Consolidated a lot of git operations toward the bottom of the
  entrypoint script to avoid popping in & out of the clone directory
  more than needed.
- Use `clone` instead of `init` + `pull` for simpler logic and automatic
  `origin` remote to make later operations simpler.
- The final `git push` command has been simplified greatly.

* Use `GH_NAME` in the clone URL.