docs(developers): require glide 0.12.0
docs(developers): require glide 0.12.0

ref: #1310

michelleN/deployment-manager,fibonacci1729/helm,technosophos/deployment-manager,jascott1/helm,helm/helm,technosophos/k8s-helm,helm/helm,qwangrepos/helm,appscode/helm,bacongobbler/helm,technosophos/deployment-manager,appscode/helm,qwangrepos/helm,rbwsam/helm,thomastaylor312/helm,flynnduism/helm,kdada/helm,adamreese/deployment-manager,bradj/helm,technosophos/k8s-helm,thomastaylor312/helm,FengyunPan/helm,flynnduism/helm,iamzhout/helm,adamreese/deployment-manager,eicnix/helm,sushilkm/helm,bradj/helm,iamzhout/helm,adamreese/deployment-manager,yan234280533/helm,jascott1/helm,eicnix/helm,SlickNik/helm,fibonacci1729/helm,technosophos/deployment-manager,SlickNik/helm,sushilkm/helm,technosophos/deployment-manager,FengyunPan/helm,adamreese/helm,adamreese/deployment-manager,yan234280533/helm,adamreese/helm,michelleN/deployment-manager,technosophos/deployment-manager,rbwsam/helm,michelleN/deployment-manager,michelleN/deployment-manager,bacongobbler/helm,adamreese/deployment-manager,kdada/helm