Fix K8 username prefix to match ood_core behavior

Author: treydock

hooks/k8s-bootstrap/set-k8s-creds.sh

@@ -14,7 +14,7 @@ fi
 # shellcheck disable=SC1090
 source "$HOOK_ENV"
 
-K8S_USERNAME="${K8S_USERNAME_PREFIX}${ONDEMAND_USERNAME}"
+K8S_USERNAME="${K8S_USERNAME_PREFIX}-${ONDEMAND_USERNAME}"
 
 # we use pass ACCESS_TOKEN into the id-token arg. That's OK, it works and refreshes.
 sudo -u "$ONDEMAND_USERNAME" kubectl config set-credentials "$K8S_USERNAME" \