deps: update dependency com.google.protobuf:protobuf-bom to v3.19.1 (#505)

Author: renovate-bot

first-party-dependencies/pom.xml

@@ -59,7 +59,7 @@
     <gax.version>2.7.0</gax.version>
     <grpc-gcp.version>1.1.0</grpc-gcp.version>
     <guava.version>31.0.1-jre</guava.version>
-    <protobuf.version>3.18.1</protobuf.version>
+    <protobuf.version>3.19.1</protobuf.version>
     <google.api-common.version>2.0.5</google.api-common.version>
     <google.common-protos.version>2.6.0</google.common-protos.version>
     <google.core.version>2.2.0</google.core.version>