Updated Checkout action version & Ubuntu OS version

[auvipy]

An attempt to fix a issue on a PR

[auvipy]

got two type of message here:

1. with python 3.6

Download action repository 'actions/checkout@v4' (SHA:3df4ab11eba7bda6032a0b82a6bb43b11571feac)
Warning: Failed to download action 'https://api.github.com/repos/actions/checkout/tarball/3df4ab11eba7bda6032a0b82a6bb43b11571feac'. Error: Response status code does not indicate success: 503 (Service Unavailable).
Warning: Back off 25.919 seconds before retry.
Warning: Failed to download action 'https://api.github.com/repos/actions/checkout/tarball/3df4ab11eba7bda6032a0b82a6bb43b11571feac'. Error: Response status code does not indicate success: 503 (Service Unavailable).
Warning: Back off 26.035 seconds before retry.
Error: Response status code does not indicate success: 503 (Service Unavailable).

[auvipy]

And with python 3.7:

---------- coverage: platform linux, python 3.7.17-final-0 -----------
Coverage XML written to file coverage.xml

=========================== short test summary info ============================
SKIPPED [1] tests/test_decorators.py:192: HTTPMethod was added in Python 3.11
SKIPPED [1] tests/test_model_serializer.py:466: has models.JSONField
SKIPPED [1] tests/test_serializer.py:747: dictionary union operator requires Python 3.9 or higher
================= 1552 passed, 3 skipped, 4 warnings in 22.12s =================
.pkg: _exit> python /opt/hostedtoolcache/Python/3.7.17/x64/lib/python3.7/site-packages

[auvipy]

we can't upgrade Ubuntu OS until we drop python 3.6 from CI