Update ci badge in the readme

The badge did still point to travis which is not used any longer.  The
new batch points to our github actions and shows the status of the
action in the check.yml file.

README.md

@@ -1,4 +1,4 @@
-[![Build Status][travis-img]][travis]
+[![Build Status]][ghactions]
 [![Code Climate][codeclimate-img]][codeclimate]
 [![Codacy Grade][codacy-grade-img]][codacy-grade]
 [![Codacy Coverage][codacy-coverage-img]][codacy-coverage]
@@ -59,8 +59,8 @@ See the [manual][docs] for more usage info.
 [FAQ]: http://alot.readthedocs.io/en/latest/faq.html
 [features]: https://github.com/pazz/alot/issues?labels=feature
 
-[travis]: https://travis-ci.com/pazz/alot
-[travis-img]: https://travis-ci.com/pazz/alot.svg?branch=master
+[Build Status]: https://github.com/pazz/alot/actions/workflows/check.yml/badge.svg
+[ghactions]: https://github.com/pazz/alot/actions
 [codacy-coverage]: https://www.codacy.com/app/patricktotzke/alot?utm_source=github.com&utm_medium=referral&utm_content=pazz/alot&utm_campaign=Badge_Coverage
 [codacy-coverage-img]: https://api.codacy.com/project/badge/Coverage/fa7c4a567cd546568a12e88c57f9dbd6
 [codacy-grade]: https://www.codacy.com/app/patricktotzke/alot?utm_source=github.com&utm_medium=referral&utm_content=pazz/alot&utm_campaign=Badge_Grade