build: Update actions from node12 to 16

checkout@v2 and setup-python@v2 are Node 12 and deprecated

.github/workflows/mkdocs_build.yml

@@ -26,10 +26,10 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
         with:
-          python-version: 3.8
+          python-version: '3.10'
       # Runs a single command using the runners shell
       - name: Run a one-line script
         run: |