Add the Coveralls step to the Github Actions workflow

[izeigerman]

No description provided.

[coveralls]

Coverage remained the same at 96.649% when pulling a9cc5b8 on coveralls-github-actions into 02a453e on master.

[izeigerman]

Ended up using the coveralls-python directly. See the issue for details.

[izeigerman]

The runtime for r_lang is rather ridiculous. @StrikerRUS I'm leaning towards following your advice and keep it on Travis for now. Although I don't like the idea of using 2 services for the exact same purpose but it appears to be a lesser evil than a ~180 minute long runtime. What do you think?

Otherwise Coveralls seems to be working with Github Actions 🎉

[StrikerRUS]

I think we can drop Travis CI for now. I have one idea how to fix long R runtime tests. If it doesn't work, we can add Travis config with only R job back. I believe that with current frequency of PRs long CI jobs are not something crucial for us.

[StrikerRUS]

Thanks a lot for setting up Coveralls for GitHub Actions! Just two minor comments below.

[izeigerman]

@StrikerRUS thanks for the review! I've addressed your comments and dropped the Travis config.

[izeigerman]

@StrikerRUS I've just realized that it's super annoying to maintain the list of required checks using their names since we can reshuffle language E2E tests. Plus github stores the history of all builds:

The list of checks will keep growing and picking the right check will become rather error prone. I wonder whether we should consider removing the LANG variable from the job name. It will look less nice but at least it should be easier to maintain.

[StrikerRUS]

it's super annoying to maintain the list of required checks

Yeah! It is absolutely true. We have already faced this problem in LightGBM repo.

I wonder whether we should consider removing the LANG variable from the job name.

Sounds reasonable! Please feel free to choose any job name that will help to maintain checks list with less pain.