for erpnext custom styles installing App to ERPNext
bench get-app customstyle https://github.com/michaeleino/erpnext-customstyle.git
bench install-app customstyle
use bench exlude-app for all apps that needed not to be updated for ex:
bench exclude-app erpnext
bench exclude-app frappe
then run
bench update
OR
git -C apps/customstyle/customstyle pull
then
bench update --build --no-backup
MIT