ref: https://stackoverflow.com/questions/2144406/how-to-make-shallow-git-submodules
1# First time shallow clone (Or you can mofify .gitmodules manually instead of this command)2git submodule add --depth 1 [email protected]:lorem/ipsum.git path/to/submodule3
4# set permanently to shallow clone (like for deploying)5git config -f .gitmodules submodule.path/to/submodule.shallow true