Depend on rosidl_generator_cpp

It's not clear why this dependency is required.

Signed-off-by: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>

Author: ivanpauno

rcljava/package.xml

@@ -42,6 +42,8 @@
   <test_depend>rmw_implementation_cmake</test_depend>
   <test_depend>rmw</test_depend>
   <test_depend>rosidl_runtime_c</test_depend>
+  <!--TODO(ivanpauno): we need this for some strange reason to make test builds-->
+  <test_depend>rosidl_generator_cpp</test_depend>
   <test_depend>rosidl_generator_java</test_depend>
   <test_depend>std_msgs</test_depend>