Hide warning about unrecognised column names

[jayvdb]

I do not want to change my label names, and I also dont want to see the warning every time I load gh-board.

You are viewing a repository that does not have any properly formatted labels...

Can we have a setting to not show that warning?
I dont mind it showing "Uncategorised", although there is probably a better default UI when labels are not numbered, but that is beyond the scope of this issue.