Check links automatically

[pattacini]

Hi @traversaro

I've just seen that you starred https://github.com/linkchecker/linkchecker ⭐
Then, we might consider using this link-checking utility to crawl our documentation for broken links.

This can be done in the GH Action.
We need to properly set up the tool though.

[traversaro]

Yes, I set it up some time ago in https://github.com/robotology-playground/codyco-docs-linkchecker, but some recent link breakages (caused by the new IIT website) reminded that we should set it up it again (with a schedule job, to detect regressions in external links).

[pattacini]

Implemented in #139.

[pattacini]

Actually, linkchecker found 3 errors ✨
See https://github.com/icub-tech-iit/documentation/runs/2906462464?check_suite_focus=true.

[pattacini]

Fixed!

[maggia80]

cool!!!