Improve publish GHA

.github/workflows/publish_doc.yaml

@@ -1,30 +1,46 @@
 name: Publish documentation
 
-on: [push]
+on:
+  push:
+    branches:
+      - master
+  pull_request:
 
 jobs:
   build:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python
+        uses: actions/setup-python@v3
+        with:
+          python-version: "3.10"
+      - name: Upgrade pip
+        run: |
+          # install pip=>20.1 to use "pip cache dir"
+          python3 -m pip install --upgrade pip
 
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: [3.8]
+      - name: Get pip cache dir
+        id: pip-cache
+        run: echo "::set-output name=dir::$(pip cache dir)"
 
-    steps:
-    - uses: actions/checkout@v2
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
-      with:
-        python-version: ${{ matrix.python-version }}
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        if [ -f requirements-dev.txt ]; then pip install -r requirements-dev.txt; fi
-    - name: run portray
-      run: |
-        portray as_html
-    - name: Deploy to gh-pages branch
-      uses: peaceiris/actions-gh-pages@v3.7.3
-      with:
-        github_token: ${{ secrets.GITHUB_TOKEN }}
-        publish_dir: ./site
+      - name: Cache dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.pip-cache.outputs.dir }}
+          key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements-dev.txt') }}
+          restore-keys: |
+            ${{ runner.os }}-pip-
+
+      - name: Install dependencies
+        run: python3 -m pip install -r ./requirements-dev.txt
+
+      - name: run portray
+        run: |
+          portray as_html
+      - name: Deploy to gh-pages branch
+        uses: peaceiris/actions-gh-pages@v3
+        if: ${{ github.ref == 'refs/heads/master' }}
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./site