Improving readme to give executable permission to the kubectl-add.sh file.
###### Deploy k8s client extension
- Copy the ***kubectl-add.sh*** to ***/usr/local/bin/***
+- Give executable permission to the above file <br />
+ - ***chmod +x /usr/local/bin/kubectl-add.sh***
###### Deploy k8s CRD artifacts
> ##### Deploying wso2-system namespace in the k8s cluster
