deps: update dependency com.google.googlejavaformat:google-java-format to v1.20.0 (#6454)

Author: renovate-bot

google-cloud-bom/pom.xml

@@ -290,7 +290,7 @@
           <dependency>
             <groupId>com.google.googlejavaformat</groupId>
             <artifactId>google-java-format</artifactId>
-            <version>1.19.2</version>
+            <version>1.20.0</version>
           </dependency>
         </dependencies>
       </plugin>