Add badges

[HexDecimal]

These are useful for quick information and navigation. Mostly useful as a way to get to the PyPI page from GitHub and then to the GitHub pages from the readme on PyPI.

• [x] @kvas-it, I don't have the permissions for the Codecov badge. You'll need to go here and give me the markdown badge, or at least the API token. https://app.codecov.io/gh/kvas-it/pytest-console-scripts/settings/badge

I've added the ones I'm interested in, you can see https://shields.io/ if you're curious about other options.

See the readme here for that these look like: https://github.com/HexDecimal/pytest-console-scripts/tree/add-badges

[codecov[bot]]

Codecov Report

Merging #71 (63aa51a) into master (1e3d815) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 63aa51a differs from pull request most recent head 2d85d37. Consider uploading reports for the commit 2d85d37 to get more accurate results

@@           Coverage Diff           @@
##           master      #71   +/-   ##
=======================================
  Coverage   99.54%   99.54%           
=======================================
  Files           1        1           
  Lines         219      219           
=======================================
  Hits          218      218           
  Misses          1        1           

[kvas-it]

Yeah, the badges look nice. Here's the code for the codecov badge:

[![codecov](https://codecov.io/gh/kvas-it/pytest-console-scripts/branch/master/graph/badge.svg?token=RfELxcqvpF)](https://codecov.io/gh/kvas-it/pytest-console-scripts)