deps: update gax.version to v2.9.0 (googleapis#573)

Author: renovate-bot

first-party-dependencies/pom.xml

@@ -56,7 +56,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <site.installationModule>${project.artifactId}</site.installationModule>
     <grpc.version>1.43.2</grpc.version>
-    <gax.version>2.8.1</gax.version>
+    <gax.version>2.9.0</gax.version>
     <grpc-gcp.version>1.1.0</grpc-gcp.version>
     <guava.version>31.0.1-jre</guava.version>
     <protobuf.version>3.19.2</protobuf.version>