https://stackoverflow.com/a/21211232/1351857
git rm -rf the/submodule
rm -rf .git/modules/the/submodule
git config -f .git/config --remove-section submodule.the/submodule 2> /dev/null
https://stackoverflow.com/a/21211232/1351857
git rm -rf the/submodule
rm -rf .git/modules/the/submodule
git config -f .git/config --remove-section submodule.the/submodule 2> /dev/null