chore(readme): change link to examples to folder to be absolute (#654)

this fixes #653

Author: Rick Rackow

README.md

@@ -18,7 +18,7 @@ This module is meant for use with Terraform 0.12. If you haven't
 intended for Terraform 0.11.x is [3.0.0].
 
 ## Usage
-There are multiple examples included in the [examples](./examples/) folder but simple usage is as follows:
+There are multiple examples included in the [examples](https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/examples/) folder but simple usage is as follows:
 
 ```hcl
 module "gke" {