test(deps): update dependency io.grpc:protoc-gen-grpc-java to v1.56.0 (#1793)

* test(deps): update dependency io.grpc:protoc-gen-grpc-java to v1.56.0

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: renovate-bot

google-cloud-bigtable/pom.xml

@@ -38,7 +38,7 @@
     <bigtable.cfe-data-batch-endpoint>batch-bigtable.googleapis.com:443</bigtable.cfe-data-batch-endpoint>
 
     <!-- These are needed to compile the protobuf used by Changestream merging acceptance test. -->
-    <test-protoc-grpc.version>1.55.1</test-protoc-grpc.version>
+    <test-protoc-grpc.version>1.56.0</test-protoc-grpc.version>
     <test-protoc.version>3.23.2</test-protoc.version>
   </properties>