Bump protobuf-java from 3.21.2 to 3.21.7

Bumps [protobuf-java](https://github.com/protocolbuffers/protobuf) from 3.21.2 to 3.21.7.
- [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...v3.21.7)

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

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -54,7 +54,7 @@ under the License.
     <scala.version>2.12.10</scala.version>
     <kryo.version>4.0.2</kryo.version>
     <reef.version>0.16.0</reef.version>
-    <protobuf.version>3.21.2</protobuf.version>
+    <protobuf.version>3.21.7</protobuf.version>
     <hadoop.version>2.7.2</hadoop.version>
     <log4j.configuration>file://log4j.properties</log4j.configuration>
     <netty.version>4.1.79.Final</netty.version>