coveragepy to Github Checks API reporter

This action is needed to report coverage of python packages collected by coveragepy.

There are some services for reporting coverage. Such as coveralls and codecov. They have drawbacks:

• they require you to have an account;
• they require you to provide them with your a email (through a permission on GH, without granting it nothing works);
• some of them require you to provide them with tokens. Tokens have to be kept secretly, so setting up a token for each repo is too much burden.
• another one uses your GitHub tokens for that and sends it onto an own server. I don't trust them with that.

So we have a different approach. GitHub has a feature allowing custom apps to annotate source code with warnings. So we just create annotations for uncovered lines.

All this is implemented in coverage2GHChecksAnnotations.py python package, if you don't want to use this action, you can use it in your workflows as you like.

This Action assummes python packaging system being already bootstrapped.

It is strongly recommended not to use the snippet below, but to fork this repo (and all the libs used) and audit it and use your fork in your projects.

on:
  push:
    branches: [ "master" ]
  pull_request:
    branches: [ "master" ]

jobs:
  build:
    runs-on: ubuntu-20.04
    steps:
      - name: annotate the stuff with coverage info
        uses: KOLANICH-GHActions/coveragepyReport@master
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}