deps: update googleapis/java-cloud-bom digest to c6d3b55

Author: renovate-bot

.github/workflows/ci.yaml

@@ -450,7 +450,7 @@ jobs:
       run: |
         mvn install -B -ntp -DskipTests -Dclirr.skip -Dcheckstyle.skip -Dfmt.skip
     - name: Validate gapic-generator-java-bom
-      uses: googleapis/java-cloud-bom/tests/validate-bom@47ad868794c5d38ee7eb95d69371a7a79f84d890
+      uses: googleapis/java-cloud-bom/tests/validate-bom@c6d3b55d73ca965a06e0de07a5ff41dc75c39219
       with:
         bom-path: gapic-generator-java-bom/pom.xml