github/workflows: test Python 3.12

crossbar is not compatible with Python 3.12, yet: [1] and [2] are not
part of a release. A release will probably take some more time [3][4].

We shouldn't advertise Python 3.12 support until that happens. But we
can make sure that everything else keeps working fine with Python 3.12
by running the test suite. A previous commit marked the failing crossbar
tests as XFAIL for 3.12.

[1] crossbario/crossbar#2091
[2] crossbario/crossbar#2093
[3] crossbario/crossbar#2093 (comment)
[4] crossbario/crossbar#2091 (comment)

Signed-off-by: Bastian Krause <bst@pengutronix.de>

.github/workflows/push-pr-unit-tests.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
     uses: ./.github/workflows/reusable-unit-tests.yml
     with:
       python-version: ${{ matrix.python-version }}

.github/workflows/scheduled-unit-tests.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
         branch: ['master']
     uses: ./.github/workflows/reusable-unit-tests.yml
     with: