Add workflow status badge to README

Author: paulyoung

README.md

@@ -1,6 +1,7 @@
 # git-remote-icp
 
 ![](https://img.shields.io/badge/status%EF%B8%8F-experimental-blueviolet)
+![](https://github.com/codebase-labs/git-remote-icp/actions/workflows/nix.yml/badge.svg?event=push)
 
 A [Git remote helper](https://git-scm.com/docs/gitremote-helpers) for the [Internet Computer](https://internetcomputer.org) Protocol.