Maintenance update

[fmigneault]

Changes

• Add support of Python 3.12.

[!NOTE]
Requires patch of authomatic.six.moves in magpie.__init__.py to work around vendor-specific definitions. Fix inspiration from https://github.com/dpkp/kafka-python/issues/2401#issuecomment-1760208950. Pending official fix (see https://github.com/authomatic/authomatic/issues/233).

• Drop support of Python 3.5, 3.6 and 3.7. Minimum version is Python 3.8.
• Pin gunicorn>=22 to address CVE-2024-1135.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 80.88%. Comparing base (d899bd2) to head (c59b2c9). Report is 4 commits behind head on master.

Files	Patch %	Lines
magpie/__init__.py	0.00%	4 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #606 +/- ## ========================================== - Coverage 80.92% 80.88% -0.04% ========================================== Files 73 73 Lines 10196 10201 +5 Branches 1824 1825 +1 ========================================== Hits 8251 8251 - Misses 1622 1626 +4 - Partials 323 324 +1 ```

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[fmigneault]

[!NOTE] Failing tests (ubuntu-latest, 3.7, false, test-local) is expected, since it was removed from the CI. The rule will be removed from the PR merge requirements once this PR is integrated (such that any PR in the meantime still respect the requirement). Coverage diff is only related to the Python 3.12 patch, which is not worth testing by itself (the fact that all other tests executed with 3.12 is enough of an indicator that it works).