[texdoc] commit email with github webhooks?

[Karl Berry]

Since texdoc development moved to github, the commit mail notifications
(lists.tug.org/texdoc-commits) no longer includes diffs, making it much
less useful. (There is a url to see them, but that is not the same as
having them directly.)

Also, github is killing the email notification feature. I presume there
is some equivalent way to do it in their new world with (I guess)
"webhooks" or "apps". Some simple searches didn't turn up a recipe,
though. Maybe someone here knows, or is willing to look into it?

(I write to the list here because Takuto, Norbert, and I didn't know
offhand, and thought someone else might.) --thanks, karl.