explicitly requires "cv_bridge" package

on package uuv_sensor_ros_plugins, the file "gazebo_ros_image_sonar.cpp" includes
"cv_bridge/cv_bridge.h". This commit fixes the following error:
uuv_simulator/uuv_sensor_plugins/uuv_sensor_ros_plugins/src/gazebo_ros_image_sonar.cpp:50:33: fatal error: cv_bridge/cv_bridge.h: No such file or directory


Signed-off-by: Diego Cesar <dcesar@krakenrobotik.de>

uuv_sensor_plugins/uuv_sensor_ros_plugins/CMakeLists.txt

@@ -19,7 +19,8 @@ find_package(catkin REQUIRED COMPONENTS
   message_filters
   tf2_ros
   tf2
-  laser_geometry)
+  laser_geometry
+  cv_bridge)
 
 find_package(Eigen3 REQUIRED)
 find_package(OGRE REQUIRED)