Increase script portability
Increase script portability

Instead of presuming that bash is installed at /bin/bash, use `$PATH`.  Official [bash docker container](https://hub.docker.com/_/bash/) installs bash at `/usr/local/bin` and recommends the use of `env`
SlickNik/helm,adamreese/helm,fibonacci1729/helm,technosophos/deployment-manager,helm/helm,adamreese/deployment-manager,eicnix/helm,adamreese/deployment-manager,bacongobbler/helm,technosophos/deployment-manager,helm/helm,technosophos/deployment-manager,jascott1/helm,michelleN/deployment-manager,technosophos/deployment-manager,adamreese/deployment-manager,technosophos/k8s-helm,eicnix/helm,fibonacci1729/helm,michelleN/deployment-manager,appscode/helm,technosophos/k8s-helm,adamreese/deployment-manager,michelleN/deployment-manager,SlickNik/helm,michelleN/deployment-manager,adamreese/deployment-manager,appscode/helm,jascott1/helm,adamreese/helm,technosophos/deployment-manager,bacongobbler/helm