Update pre-release yaml.
Update pre-release yaml.

This commit will do following:

1. Add label "openebs.io/cas-type: cstor" to storagepool
2. Add disk names in storagepool

Signed-off-by: sonasingh46 <432bc762d0f8cc24631693b9769f7b554138faf9@gmail.com>

yudaykiran/openebs