use sigs.k8s.io/yaml instead of gopkg.in/yaml.v2
use sigs.k8s.io/yaml instead of gopkg.in/yaml.v2

this is for consistency as everywhere we use sigs.k8s.io/yaml package

Signed-off-by: Karuppiah Natarajan <5381d7ea77d6a38987baf491e984bbfa7ce00eba@gmail.com>

adamreese/deployment-manager,adamreese/deployment-manager,michelleN/deployment-manager,bacongobbler/helm,adamreese/helm,bacongobbler/helm,adamreese/helm,michelleN/deployment-manager,michelleN/deployment-manager,michelleN/deployment-manager,helm/helm,adamreese/deployment-manager,helm/helm,adamreese/deployment-manager,adamreese/deployment-manager