Process xacro file test

[JesusSilvaUtrera]

🎉 New feature

Closes #92

Summary

Added a pytest unit test to process the main xacro file (andino.urdf.xacro) to check it is well formatted.

Test it

Build the package and then you can test it running colcon test --packages-select andino_description --event-handler=console_direct+ --pytest-args -k test_xacro_processing. You will see in the therminal the output of the test and if there is any error.

Checklist

• [x] Signed all commits for DCO
• [x] Added tests
• [x] Added example and/or tutorial
• [ ] Updated documentation (as needed)

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[JesusSilvaUtrera]

The only doubt I have here is whether it would be necessary to add to the documentation the test part or not.

[JesusSilvaUtrera]

@jballoffet all comments addressed.