Update README.md (#3)

README.md

@@ -15,12 +15,16 @@ ensures that when a dependency update happens, a tarball is downloaded.
 In your workflow, simply add the following:
 
 ```yaml
-Coming Soon
+---
+steps:
+  - name: ":helm: Helm Tarball Update"
+    plugins:
+      github.com/equinixmetal-buildkite/helm-tar-update-buildkite-plugin#v0.0.1: {}
 ```
 
 This will make sure that for any pull request that updates Helm dependencies,
 the tarball for those dependencies will be downloaded and commited to appropriate
 branch to come along the pull request.
 
 Note that this will only happen if you keep a `charts` directory with your Helm
-chart.
+chart.