docs: add commitizen badge

Eli Skeggs · Eli Skeggs · commit a14ee5a884a8 · 2019-10-29T23:47:59.000-07:00
diff --git a/README.md b/README.md
@@ -1,5 +1,7 @@
 # commitlint-jenkins
 
+[![Commitizen friendly](https://img.shields.io/badge/commitizen-friendly-brightgreen.svg)](http://commitizen.github.io/cz-cli/)
+
 A wrapper for commitlint that determines the appropriate commit range in a Jenkins build. Adapted
 from `@commitlint/travis-cli`.
 
