Replace underscored commands with dasherized commands

[cmitz]

Implements #10 .

I really have no experience in python stuff and it might be better to just use proper versioning, but for now this will have to do.

[Dog]

Good job finding that breaking change with click.

I think pinning the versions would be a good idea to do in this file:
https://github.com/uw-ipd/github-checks-buildkite-plugin/blob/master/ghapp/requirements.txt#L1

If you'd like to do it as well you can find more information on it here:
https://pip.readthedocs.io/en/1.1/requirements.html#the-requirements-file-format

The final say would be up to the maintainers.

[cmitz]

Thanks. Unfortunately, I do not have the time to make extra commits, because I have plenty of work left to do in the other parts of our Buildkite pipeline stuff.

[asford]

Yikes, that is a rather nasty change between click 6->7, pinning makes the most sense to me. @Dog would you be willing to open PR for that?