deps: update dependency com.google.googlejavaformat:google-java-format to v1.21.0

Author: renovate-bot

gapic-generator-java/pom.xml

@@ -441,7 +441,7 @@
     <dependency>
       <groupId>com.google.googlejavaformat</groupId>
       <artifactId>google-java-format</artifactId>
-      <version>1.7</version>
+      <version>1.21.0</version>
     </dependency>
     <dependency>
       <groupId>junit</groupId>

gax-java/dependencies.properties

@@ -27,7 +27,7 @@ version.gax_httpjson=2.45.1-SNAPSHOT
 # not for self-service clients (from googleapis project).
 
 version.com_google_protobuf=3.25.2
-version.google_java_format=1.15.0
+version.google_java_format=1.21.0
 version.io_grpc=1.62.2
 
 # Maven artifacts.