Use the gradle plugin (same usage as in element-android) to standardise caching.

This may or may not speed up build times.

.github/workflows/build.yml

@@ -28,6 +28,10 @@ jobs:
           # Ensure we are building the branch and not the branch after being merged on develop
           # https://github.com/actions/checkout/issues/881
           ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.ref }}
+      - name: Configure gradle
+        uses: gradle/gradle-build-action@v2
+        with:
+          cache-read-only: ${{ github.ref != 'refs/heads/develop' }}
       - name: Assemble debug APK
         run: ./gradlew assembleDebug $CI_GRADLE_ARG_PROPERTIES
       - name: Upload debug APKs