Sending a warning instead of throwing error when KUBECONFIG is missing. (#146)

lib/run.js

@@ -53,7 +53,7 @@ function installKubectl(version) {
 }
 function checkClusterContext() {
     if (!process.env["KUBECONFIG"]) {
-        throw new Error('Cluster context not set. Use k8ssetcontext action to set cluster context');
+        core.warning('KUBECONFIG env is not explicitly set. Ensure cluster context is set by using k8s-set-context / aks-set-context action.');
     }
 }
 function run() {