Bump protobuf-java from 3.21.2 to 3.21.3

Bumps [protobuf-java](https://github.com/protocolbuffers/protobuf) from 3.21.2 to 3.21.3.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](protocolbuffers/protobuf@v3.21.2...v3.21.3)

---
updated-dependencies:
- dependency-name: com.google.protobuf:protobuf-java
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

pom.xml

@@ -39,7 +39,7 @@
     -->
     <guava.jre.version>31.1-jre</guava.jre.version>
     <gwt.version>2.9.0</gwt.version>
-    <protobuf.version>3.21.2</protobuf.version>
+    <protobuf.version>3.21.3</protobuf.version>
     <!-- Property for protobuf-lite protocArtifact, which isn't a "normal" Maven dep. -->
     <!-- TODO(cpovirk): Use protobuf.version instead. But that requires finding the new way to request the Lite runtime. -->
     <protobuf-lite.protoc.version>3.1.0</protobuf-lite.protoc.version>