Update gradle/actions action to v5 (#8)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/backend.yaml

@@ -30,7 +30,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v4
+        uses: gradle/actions/setup-gradle@v5
 
       - name: Test
         run: ./gradlew clean check