docs: add conventional commits badge to README (#104)

Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>

README.md

@@ -2,7 +2,7 @@
   <h1 align="center">Conform</h1>
   <p align="center">Policy enforcement for your pipelines.</p>
   <p align="center">
-    <a href="https://gitter.im/autonomy/conform"><img alt="Gitter" src="https://img.shields.io/gitter/room/autonomy/conform.svg?style=flat-square"></a>
+    <a href="https://conventionalcommits.org"><img alt="Conventional Commits" src="https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg?style=flat-square"></a>
     <a href="https://godoc.org/github.com/autonomy/conform"><img alt="GoDoc" src="http://img.shields.io/badge/godoc-reference-blue.svg?style=flat-square"></a>
     <a href="https://travis-ci.org/autonomy/conform"><img alt="Travis" src="https://img.shields.io/travis/autonomy/conform.svg?style=flat-square"></a>
     <a href="https://codecov.io/gh/autonomy/conform"><img alt="Codecov" src="https://img.shields.io/codecov/c/github/autonomy/conform.svg?style=flat-square"></a>