Update README.md

Author: coryleach

README.md

@@ -3,6 +3,8 @@
 ![version](https://img.shields.io/badge/version-1.0.3-blue.svg?cacheSeconds=2592000)
 [![openupm](https://img.shields.io/npm/v/com.gameframe.async?label=openupm&registry_uri=https://package.openupm.com)](https://openupm.com/packages/com.gameframe.async/)
 [![Codacy Badge](https://app.codacy.com/project/badge/Grade/d2749fdbc70f422a9d1efccb56d48bff)](https://www.codacy.com/manual/coryleach/UnityAsync?utm_source=github.com&utm_medium=referral&utm_content=coryleach/UnityAsync&utm_campaign=Badge_Grade)
+[![license](https://img.shields.io/github/license/coryleach/UnityAsync)](https://github.com/coryleach/UnityAsync/blob/master/LICENSE)
+
 [![twitter](https://img.shields.io/twitter/follow/coryleach.svg?style=social)](https://twitter.com/coryleach)
 
 > Async task utility package for Unity</br>