Merge pull request #1037 from wxmerkt/topic/make-example-robot-data-optional

Make example-robot-data an optional dependency
6 jobs for devel in 31 minutes and 24 seconds (queued for 2 seconds)
Name Stage Failure
robotpkg-py-crocoddyl-buster Test
Total Test time (real) =  33.59 sec

The following tests FAILED:
15 - test_actions (Child aborted)
16 - test_diff_actions (Child aborted)
Errors while running CTest
make: *** [Makefile:110: test] Error 8
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1