Add functionality to set the issue/PR assignees

[adrn]

This adds methods to add an assignee or set the assignees for an issue or pull request.

I guess this is a work in progress, because I haven't tested it, so I'm not even sure it works :)! Any ideas on how to test this?

cc @astrofrog @pllim @Cadair

[pllim]

add_assignees can be easily tested, but I don't see how we can test set_assignees meaningfully with mock. We might have to #yolo that one.

Also, please fix PEP 8:

/home/travis/build/OpenAstronomy/baldrick/baldrick/github/github_api.py:455:39: E261 at least two spaces before inline comment

[codecov-io]

Codecov Report

Merging #76 into master will decrease coverage by 0.57%.
The diff coverage is 25%.

@@            Coverage Diff             @@
##           master      #76      +/-   ##
==========================================
- Coverage   82.72%   82.15%   -0.58%     
==========================================
  Files          16       16              
  Lines         799      807       +8     
==========================================
+ Hits          661      663       +2     
- Misses        138      144       +6

Impacted Files	Coverage Δ
baldrick/github/github_api.py	63.97% <25%> (-1%)	⬇️

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[astrofrog]

To try out things that require authentication, see https://baldrick.readthedocs.io/en/latest/local.html - however this requires secret keys that we can't easily all share. I'll try it out for now.

[astrofrog]

I pushed a small fix to the URL, but otherwise the main issue is that the bot can only assign users to issues/PRs if we give it push access to the repo... Too much power?

[pllim]

give it push access to the repo

That is scary... What if the bot squash all commits in master into one commit? 😱 Can we give it really limited push access; like it can label issues but cannot modify code, something like that?

[bsipocz]

can you give a "triaging" level access to the bot? After all it exists for exactly similar use cases (though it's for users, so may not yet be applicable for bots?)

[astrofrog]

I'll investigate the triaging option