Add DOI badge, remove TravisCI

Also remove a space.

Author: RichardLitt

readme.md

@@ -1,7 +1,7 @@
-# doi-regex 
+# doi-regex
 
-[![Build Status](https://travis-ci.org/regexhq/doi-regex.svg?branch=master)](https://travis-ci.org/regexhq/doi-regex)
 [![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fregexhq%2Fdoi-regex.svg?type=shield)](https://app.fossa.io/projects/git%2Bgithub.com%2Fregexhq%2Fdoi-regex?ref=badge_shield)
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.11197208.svg)](https://doi.org/10.5281/zenodo.11197208)
 
 > Regular expression for matching DOIs