build: Update to allow tests to run on python 3.11

* Update so tox will allow running on the new version.
* Update so the hosted runner actually respects the python version in
  the matrix

.github/workflows/unit-tests.yml

@@ -57,15 +57,20 @@ jobs:
             sudo apt-get update && sudo apt-get install -y mongodb-org="${{ matrix.mongo-version }}.*"
           fi
 
-      - name: checkout repo
-        uses: actions/checkout@v3
-
       - name: start mongod server for tests
         run: |
           sudo mkdir -p /data/db
           sudo chmod -R a+rw /data/db
           mongod &
 
+      - name: Setup Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: checkout repo
+        uses: actions/checkout@v3
+
       - name: install requirements
         run: |
           sudo make test-requirements

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py38, quality
+envlist = py{38,311} quality
 
 # This is needed to prevent the lms, cms, and openedx packages inside the "Open
 # edX" package (defined in setup.py) from getting installed into site-packages