Re-enable go test in CircleCI (#173)

Author: wing328

CI/pom.xml.circleci

@@ -855,7 +855,7 @@
                 <module>samples/client/petstore/kotlin-threetenbp/</module>
                 <module>samples/client/petstore/kotlin-string/</module>
                 <!-- test non-java projects -->
-                <!--<module>samples/client/petstore/go</module>-->
+                <module>samples/client/petstore/go</module>
                 <!-- servers -->
                 <module>samples/server/petstore/java-vertx/rx</module>
                 <module>samples/server/petstore/java-vertx/async</module>