Upgrade the k8s version of the cluster being used in the OEP pipeline to 1.15.
Reason for upgrade:
Test the compatibilty/issues of DOP deployment on k8s version 1.15.
To use openEBS localpv storage class we need k8s version greater than 1.12 and we need to use it for deploying DOP in the pipelines. (currently, we are using standard storage class in DOP deployment)
Issue:
Reason for upgrade: