deps: update dependency com.google.protobuf:protobuf-java to v3.12.2 (#1527)

Author: renovate-bot

pom.xml

@@ -453,7 +453,7 @@
     <project.oauth.version>1.30.6</project.oauth.version>
     <project.jsr305.version>3.0.2</project.jsr305.version>
     <project.gson.version>2.8.6</project.gson.version>
-    <project.protobuf-java.version>3.11.4</project.protobuf-java.version>
+    <project.protobuf-java.version>3.12.2</project.protobuf-java.version>
     <project.guava.version>29.0-android</project.guava.version>
     <project.appengine.version>1.9.78</project.appengine.version>
     <project.xpp3.version>1.1.4c</project.xpp3.version>