consider shallow git clone for create `get()` function

[grahamwhaley]

I'm wondering if it will be possible to use a shallow clone in the get function of the create_stack.sh code - right now I'm staring at quite a big download waiting for the efk to pull - and I suspect 90% of it is not needed. The code is currently:

function get_repo() {
	local repo="${1}"
	local path="${2}"
	clone_dir=$(basename "${repo}" .git)
	[[ -d "${path}/${clone_dir}" ]] || git -C "${path}" clone "${repo}"

}