Bump protobuf.version from 3.21.6 to 3.21.7

Bumps `protobuf.version` from 3.21.6 to 3.21.7.

Updates `protobuf-java` from 3.21.6 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@v3.21.6...v3.21.7)

Updates `protobuf-java-util` from 3.21.6 to 3.21.7

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

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

pom.xml

@@ -20,7 +20,7 @@
         <!-- name of parameter changed in latest mvn javadoc plugin version-->
         <additionalOptions>-Xdoclint:none</additionalOptions>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <protobuf.version>3.21.6</protobuf.version>
+        <protobuf.version>3.21.7</protobuf.version>
         <testcontainers.version>1.17.3</testcontainers.version>
         <kafka-libs.version>7.2.1</kafka-libs.version>
     </properties>