Add setup gradle step to pages pipeline

Author: nsk90

.github/workflows/pages.yml

@@ -46,6 +46,8 @@ jobs:
       - name: Setup Pages
         id: pages
         uses: actions/configure-pages@v5
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
       - name: Run Dokka
         run: ./gradlew dokkaGenerate
         working-directory: '${{ github.workspace }}'