Update actions/cache action to v6

Author: renovate[bot]

.github/workflows/actions.yml

@@ -27,13 +27,13 @@ jobs:
         with:
           gradle-version: '9.6.0'
       - name: Cache SonarCloud packages
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: ~/.sonar/cache
           key: ${{ runner.os }}-sonar-${{ hashFiles('**/build.gradle') }}
           restore-keys: ${{ runner.os }}-sonar-
       - name: Cache Gradle packages
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: |
             ~/.gradle/caches