add test status badge

Author: indooorsman

readme.md

@@ -1,6 +1,7 @@
 # esbuild-css-modules-plugin
 
 [![npm version](https://img.shields.io/npm/v/esbuild-css-modules-plugin.svg?style=flat)](https://www.npmjs.com/package/esbuild-css-modules-plugin)
+[![Test](https://github.com/indooorsman/esbuild-css-modules-plugin/actions/workflows/test.yml/badge.svg)](https://github.com/indooorsman/esbuild-css-modules-plugin/actions/workflows/test.yml)
 
 A esbuild plugin to bundle css modules into js(x)/ts(x).