Streamlining errata management

[Philippe Le Hégaret]

When Process 2018 came into effect, one of the major changes was the
ability for W3C produce an Amended Recommendation to update a
Recommendation [1], without adding new features, parallel to the way a
Working Group produces an Edited Recommendation. This was an important
update since it gave us a path to update a Recommendation if no Working
Group was chartered to maintain a Recommendation.

The transition requirement document was updated accordingly [2].

The next step was to streamline the management of errata. W3C published
a lot of Recommendations over the years and lots of them remain relevant
to today's Web.

To facilitate the editing and handling of errata, we're proposing a
workflow based on GitHub issues (kuddos to Ivan Herman for initiating it):
https://github.com/w3c/display_errata

The intent is to spread this workflow to existing W3C Recommendations
(we've been requiring all W3C Recommendations to have a GH repository
for comments since last year).

Comments here or on GH are welcome.

Philippe

[1] https://www.w3.org/2018/Process-20180201/#revised-rec
[2] https://www.w3.org/Guide/transitions?profile=CR&cr=rec-amended