Bump google-cloud-functions from 2.8.0 to 2.9.0

Bumps [google-cloud-functions](https://github.com/googleapis/google-cloud-java) from 2.8.0 to 2.9.0.
- [Release notes](https://github.com/googleapis/google-cloud-java/releases)
- [Changelog](https://github.com/googleapis/google-cloud-java/blob/main/java-document-ai/CHANGELOG.md)
- [Commits](googleapis/google-cloud-java@google-cloud-kms-v2.8.0...google-cloud-document-ai-v2.9.0)

---
updated-dependencies:
- dependency-name: com.google.cloud:google-cloud-functions
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

system-x/services/google/cloud/functions/pom.xml

@@ -13,7 +13,7 @@
     <name>TNB :: System-X :: Services :: Google :: Functions</name>
 
     <properties>
-        <google.functions.version>2.8.0</google.functions.version>
+        <google.functions.version>2.9.0</google.functions.version>
     </properties>
 
     <dependencies>