Option to fail on empty description

[litscher]

Currently a warning is thrown, but that does not prevent people from merging, when using this action as a branch protection.

[JJ]

Reopening until checked and released, to pin tests to this issue.

[JJ]

I'm seeing some issue with the logic here. bodyContains already implies allowEmpty == false, so the flow will need to be slightly changed, and maybe a bit of documentation added. Not totally sure that needs to pre-empt the release, though.
If you need this urgently I can make a pre-release as is, changing the minor only.

[JJ]

There is definitely a documentation or maybe a default value issue. The default value was included to make it have the same behavior as before, so it's behaving exactly the same, implying this error came from before, namely, bodyContains does not work if the body is empty. I think that the best way to go forward is opening this as a separate issue...