CI to run the automated tests

[avelino]

to facilitate the review of new contributions it is important to have an environment to run the tests for new pull requests autatically

options:

• https://travis-ci.com/
• https://circleci.com/

[ecanuto]

We start to use Github actions on 6de376f. Test/Vet/Lint/Fmt/Coverage on d865713.

Also, project badges on 6a7db96, 2a9ada5 and 68098c4.

I think we can now close this issue.