Fix caching GH actions on master

Author: octylFractal

.github/workflows/gradle.yml

@@ -22,7 +22,7 @@ jobs:
     - name: Setup Gradle
       uses: gradle/actions/setup-gradle@v5
       with:
-        cache-read-only: ${{ !(github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/heads/version/')) }}
+        cache-read-only: ${{ !(github.ref == 'refs/heads/master' || startsWith(github.ref, 'refs/heads/version/')) }}
 
     - name: Execute Gradle build
       run: ./gradlew build -s