Check if git submodule has been updated on remote

 Based on https://stackoverflow.com/a/3278427/7976758 I'd do something like this:

git submodule foreach git remote update
git submodule foreach git --no-pager diff origin/master master

If submodules use different branches the script needs to take that into account.

from: https://stackoverflow.com/questions/50965094/check-if-git-submodule-has-been-updated-on-remote