Add pyre badge to readme (#371)

Summary: Pull Request resolved: #371

Reviewed By: pradeep90

Differential Revision: D25927938

Pulled By: dkgi

fbshipit-source-id: 180e970acf39bb947b6a116c631900e08a3b2fb1

Author: dkgi

README.md

@@ -1,5 +1,6 @@
 ![lint](https://github.com/facebook/pyre-check/workflows/lint/badge.svg)
 ![tests](https://github.com/facebook/pyre-check/workflows/tests/badge.svg)
+![pyre](https://github.com/facebook/pyre-check/workflows/pyre/badge.svg)
 
 <p align="center">
   <img src="https://raw.githubusercontent.com/facebook/pyre-check/master/logo.png">