docs: update README

Author: BenediktFloeser

Makefile

@@ -1,34 +1,26 @@
 # GKE Authentication Plugin
 
-This plugin provides a standalone way to generate an ExecCredential for use by k8s.io/client-go applications.
+> Note: This is a hard fork of [this repo](https://github.com/traviswt/gke-auth-plugin). This version adds support for service account impersonation and uses `client.authentication.k8s.io/v1` instead of `v1beta1`
 
-Google already provides a [gke-gcloud-auth-plugin](https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke); however, that plugin depends on the gcloud CLI, which is written in Python. This dependency graph is Large if you want to authenticate and interact with a GKE cluster from a go application.
+This plugin provides a standalone way to generate an ExecCredential for use by k8s.io/client-go applications or
+human users.
 
-The plugin is for use outside of a cluster; when running in the cluster, mount a service account and use that token to interact with the Kubernetes API.
+Google already provides a [gke-gcloud-auth-plugin](https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke); however,
+that plugin depends on the gcloud CLI, which is written in Python. This dependency graph is large, if you want to authenticate and interact with a GKE cluster from a go application.
 
-## Build
-
-```shell
-make
-```
-
-Or with Docker:
-```shell
-docker build -f Dockerfile.dev -t gke-auth-plugin-dev .
-
-docker run -it --rm --name gke-auth-plugin-dev-container -v ${PWD}:/home/nonroot gke-auth-plugin-dev
-
-make
-```
+This plugin is for use outside of a cluster; when running in the cluster, mount a service account and use that token to interact with the Kubernetes API.
 
 ## Run
 
 ```shell
 # generate ExecCredential
-bin/gke-auth-plugin
+gke-auth-plugin
+
+# generate credentials for service account
+gke-auth-plugin --impersonate_service_account=${GOOGLE_SERVICE_ACCOUNT_EMAIL}
 
 # version
-bin/gke-auth-plugin version
+gke-auth-plugin version
 ```
 
 You can straight up replace the gke-gcloud-auth-plugin with this binary, or place on your path and update your kubeconfig exec command to run gke-auth-plugin.
@@ -40,11 +32,8 @@ users:
 - name: user_id
   user:
     exec:
-      apiVersion: client.authentication.k8s.io/v1beta1
+      apiVersion: client.authentication.k8s.io/v1
       command: gke-auth-plugin
       provideClusterInfo: true
       interactiveMode: Never
 ```
-## TODO
-
-- Add unit tests

README.md

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"fmt"
+
 	"github.com/spf13/cobra"
 	"github.com/traviswt/gke-auth-plugin/pkg/conf"
 )