update docs deployment - only for main pushes

.github/workflows/docs.yml

@@ -5,19 +5,28 @@ name: Deploy documentation
 
 on:
   push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
+    branches: 
+      - main
+
+permissions:
+  contents: write
 
 jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-
-      - uses: actions/setup-python@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v4
         with:
           python-version: 3.x
+
+      - run: echo "cache_id=$(date --utc '+%V')" >> $GITHUB_ENV
+      - uses: actions/cache@v3
+        with:
+          key: mkdocs-material-${{ env.cache_id }}
+          path: .cache
+          restore-keys: |
+            mkdocs-material-
 
       - run: pip install mkdocs-material mkdocs-macros-plugin