Bump protobuf-java from 3.21.8 to 3.21.9 (#375)

Bumps [protobuf-java](https://github.com/protocolbuffers/protobuf) from 3.21.8 to 3.21.9.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](https://github.com/protocolbuffers/protobuf/compare/v3.21.8...v3.21.9)

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

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

planetiler-core/pom.xml

@@ -19,7 +19,7 @@
     <geotools.version>27.2</geotools.version>
     <log4j.version>2.19.0</log4j.version>
     <prometheus.version>0.16.0</prometheus.version>
-    <protobuf.version>3.21.8</protobuf.version>
+    <protobuf.version>3.21.9</protobuf.version>
   </properties>
 
   <dependencies>