Remove tag+digest on shell-image 🍶
Remove tag+digest on shell-image 🍶

Some runtime (cri-o) do not support tag+digest notation on image
reference. Removing this on shell-image to fix the `notags` release
yamls.

Signed-off-by: Vincent Demeester <b98c0fd48a8945096c766de790fe70420dd2f223@redhat.com>

tektoncd/pipeline,tektoncd/pipeline