[core-workflow] instructions for cherrypicking a change from master

[Zachary Ware]

On Thu, Oct 6, 2016 at 10:10 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> That note about "make sure it looks good" reminded me that "make
> patchcheck" is going to need updating to handle git, which means
> updating Tools/scripts/patchcheck.py
>
> Brett, how would you like that extra task captured - PR to PEP 512?

I just checked, `make patchcheck` works fine from a Git checkout.

-- 
Zach