Update download links to 2.8.1 binaries

Author: sslavic

README.md

@@ -34,10 +34,10 @@ Think of it like apt/yum/homebrew for Kubernetes.
 
 Binary downloads of the Helm client can be found at the following links:
 
-- [OSX](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.0-darwin-amd64.tar.gz)
-- [Linux](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.0-linux-amd64.tar.gz)
-- [Linux 32-bit](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.0-linux-386.tar.gz)
-- [Windows](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.0-windows-amd64.tar.gz)
+- [OSX](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.1-darwin-amd64.tar.gz)
+- [Linux](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.1-linux-amd64.tar.gz)
+- [Linux 32-bit](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.1-linux-386.tar.gz)
+- [Windows](https://kubernetes-helm.storage.googleapis.com/helm-v2.8.1-windows-amd64.tar.gz)
 
 Unpack the `helm` binary and add it to your PATH and you are good to go!
 macOS/[homebrew](https://brew.sh/) users can also use `brew install kubernetes-helm`.