roll back 3.11 update in build

this breaks our blogging plugin, so let's hold off for a bit

example: https://github.com/the-full-stack/website/actions/runs/5179713833

Author: charlesfrye

.github/workflows/ci.yml

@@ -10,6 +10,6 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
         with:
-          python-version: 3.x
+          python-version: '3.10'
       - run: pip install -r requirements.txt
       - run: mkdocs gh-deploy --force