Switch to Python 3.11 for CI tasks

.github/workflows/core.yml

@@ -8,12 +8,12 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-20.04, windows-latest, macos-latest]
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.6", "3.7", "3.11", "3.12"]
 
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: "recursive"
 
@@ -37,7 +37,7 @@ jobs:
           tox -e lint
 
       - name: Integration Tests
-        if: ${{ matrix.python-version == '3.9' }}
+        if: ${{ matrix.python-version == '3.11' }}
         run: |
           tox -e testcore