Bump protobuf-java from 3.16.1 to 3.16.3 in /realtime

Bumps [protobuf-java](https://github.com/protocolbuffers/protobuf) from 3.16.1 to 3.16.3.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](protocolbuffers/protobuf@v3.16.1...v3.16.3)

---
updated-dependencies:
- dependency-name: com.google.protobuf:protobuf-java
  dependency-type: direct:production
...

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

Author: dependabot[bot]

realtime/pom.xml

@@ -60,7 +60,7 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
-      <version>3.16.1</version>
+      <version>3.16.3</version>
     </dependency>
     <!--<dependency>-->
       <!--<groupId>org.apache.commons</groupId>-->