python3-gitdb: upgrade 4.0.11 -> 4.0.12

python3-gitdb: upgrade 4.0.11 -> 4.0.12

Changelog:
===========
- Never add a vendored smmap directory to sys.path
- Revise and update the readme
- Set Dependabot submodule update cadence to weekly
- Add missing asserts in test_base.py
- Use contextlib.suppress instead of except: pass
- Add support for Python 3.13
- Potential Race Condition Fix - OS Rename & Chmod - PermissionError
- Bump gitdb/ext/smmap from 256c5a2 to 04dd210
- Bump actions/setup-python from 4 to 5

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>