Update ruby setup actions (fix #306)

No longer tracking Gemfile.lock

.github/workflows/pages-deploy.yml.hook

@@ -13,9 +13,6 @@ jobs:
 
     runs-on: ubuntu-latest
 
-    env:
-      GEMS_PATH: vendor/bundle
-
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -23,22 +20,10 @@ jobs:
           fetch-depth: 0  # for posts's lastmod
 
       - name: Setup Ruby
-        uses: actions/setup-ruby@v1
+        uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.7
-
-      - name: Bundle Caching
-        uses: actions/cache@v2
-        with:
-          path: ${{ env.GEMS_PATH }}
-          key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-gems-
-
-      - name: Bundle Install
-        run: |
-          bundle config path ${{ env.GEMS_PATH }}
-          bundle install --jobs 4 --retry 3
+          bundler-cache: true
 
       - name: Check baseurl
         run: |