deps: version manage error_prone_annotations to 2.5.1 (#1268)

Author: chingor13

pom.xml

@@ -126,6 +126,11 @@
         <version>1.1.2</version>
         <scope>test</scope>
       </dependency>
+      <dependency>
+        <groupId>com.google.errorprone</groupId>
+        <artifactId>error_prone_annotations</artifactId>
+        <version>2.5.1</version>
+      </dependency>
       <dependency>
         <groupId>com.google.appengine</groupId>
         <artifactId>appengine-api-1.0-sdk</artifactId>