Add a shortcut in Makefile for updating triton (#88318)
Summary: Local triton installation needs to be updated after we migrate
to a newer version of triton, e.g.
https://github.com/pytorch/pytorch/pull/88242. The Makefile shortcut
makes that easier.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88318
Approved by: https://github.com/ezyang
