ci: Remove use of action

.github/workflows/main.yml

@@ -11,10 +11,15 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Checkout master
-        uses: actions/checkout@v1
+      - uses: actions/checkout@v2
 
-      - name: Deploy to GH Pages
-        uses: mhausenblas/mkdocs-deploy-gh-pages@5498449
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Set up Python 3.x
+        uses: actions/setup-python@v2
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+
+      - name: Build and deploy
+        run: mkdocs gh-deploy --strict