docs: use peaceiris action

.github/workflows/docs.yml

@@ -1,19 +1,52 @@
-name: docs
+name: GitHub Pages
+
 on:
   push:
     branches:
       - main
+
 jobs:
   deploy:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
+    permissions:
+      contents: write
+    concurrency:
+      group: ${{ github.workflow }}-${{ github.ref }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
-      - uses: actions/setup-python@v2
-        with:
-          python-version: 3.x
-      - run: pip install mkdocs-material \
-          mkdocs-git-revision-date-localized-plugin
-      - run: mkdocs gh-deploy --force
 
+      - name: Setup Python
+        uses: actions/setup-python@v3
+        with:
+          python-version: '3.9'
+
+      - name: Upgrade pip
+        run: |
+          # install pip=>20.1 to use "pip cache dir"
+          python3 -m pip install --upgrade pip
+
+      - name: Get pip cache dir
+        id: pip-cache
+        run: echo "::set-output name=dir::$(pip cache dir)"
+
+      - name: Cache dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.pip-cache.outputs.dir }}
+          key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements-docs.txt') }}
+          restore-keys: |
+            ${{ runner.os }}-pip-
+
+      - name: Install dependencies
+        run: python3 -m pip install -r ./requirements-docs.txt
+
+      - run: mkdocs build
+
+      - name: Deploy
+        uses: peaceiris/actions-gh-pages@v3
+        if: ${{ github.ref == 'refs/heads/main' }}
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./site

requirements-docs.txt

@@ -0,0 +1,2 @@
+mkdocs-material
+mkdocs-git-revision-date-localized-plugin