readded deleted tests from MR !203 and !675

the tests-jobs for python 3.11 in the CI pipeline for gitlab and github was removed in !703 (merged) !675 (merged). this MR readd them to ensure proper CI/CD testing.

@luenensc

.github/workflows/main.yml

@@ -29,7 +29,7 @@ jobs:
       fail-fast: false
       matrix:
         os: ["windows-latest", "ubuntu-latest", "macos-latest"]
-        python-version: ["3.8", "3.9", "3.10"]
+        python-version: ["3.8", "3.9", "3.10", "3.11"]
     defaults:
       run:
         # somehow this also works for windows O.o ??