add opencv_apps

Author: v4hn

sources.repos

@@ -495,6 +495,10 @@ repositories:
     type: git
     url: https://github.com/ros-perception/open_karto.git
     version: melodic-devel
+  opencv_apps:
+    type: git
+    url: https://github.com/ros-perception/opencv_apps.git
+    version: indigo
   openni2_camera:
     type: git
     url: https://github.com/ros-o/openni2_camera.git