Update README.md

Author: iSnow

README.md

@@ -2,6 +2,7 @@
 
 [![License](https://img.shields.io/github/license/frictionlessdata/tableschema-java.svg)](https://github.com/frictionlessdata/tableschema-java/blob/master/LICENSE)
 [![Release](https://img.shields.io/jitpack/v/github/frictionlessdata/tableschema-java)](https://jitpack.io/#frictionlessdata/tableschema-java)
+[![Coverage](.github/badges/jacoco.svg)](https://github.com/frictionlessdata/tableschema-java/actions/workflows/maven.yml)
 [![Codebase](https://img.shields.io/badge/codebase-github-brightgreen)](https://github.com/frictionlessdata/tableschema-java)
 [![Support](https://img.shields.io/badge/support-discord-brightgreen)](https://discordapp.com/invite/Sewv6av)