Use python 3.11 during tests

Author: philpep

.github/workflows/release.yml

@@ -19,10 +19,10 @@ jobs:
     - uses: actions/checkout@v4
       with:
         fetch-depth: 0 # needed by setuptools-scm
-    - name: Switch to using Python 3.9 by default
+    - name: Switch to using Python 3.11 by default
       uses: actions/setup-python@v5
       with:
-        python-version: "3.9"
+        python-version: "3.11"
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip

.github/workflows/tox.yml

@@ -43,13 +43,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        toxenv: [docs, packaging, py39]
+        toxenv: [docs, packaging, py311]
     steps:
     - uses: actions/checkout@v4
-    - name: Set up Python 3.9
+    - name: Set up Python 3.11
       uses: actions/setup-python@v5
       with:
-        python-version: "3.9"
+        python-version: "3.11"
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip