deps: update googleapis/java-cloud-bom digest to 8520f37

Author: renovate-bot

.github/workflows/ci.yaml

@@ -273,7 +273,7 @@ jobs:
       run: |
         mvn install -B -ntp -DskipTests -Dclirr.skip -Dcheckstyle.skip
     - name: Validate gapic-generator-java-bom
-      uses: googleapis/java-cloud-bom/tests/validate-bom@ab98a491b510503e8ff461c42ecd3cc4e67a44cb
+      uses: googleapis/java-cloud-bom/tests/validate-bom@8520f37a8093f05a02ec0a3dc44b5d8b45f58ef9
       with:
         bom-path: gapic-generator-java-bom/pom.xml