Updating base-drafts contribution guidelines for post-IESG phase

[Lucas Pardue <[e-mail]>]

Hello all,

For a long time we've been developing the QUIC version 1 protocol documents
in the QUIC WG base-drafts GitHub repository [1] following the Late-Stage
Process.

The documents have made it through IESG review and are progressing to the
RFC editor. As previously communicated, the bar to document contributions
has been raised once again. To make this clear, we've updated our
contribution guidelines to better reflect the Post-IESG process [1], please
familiarize yourselves with them. To summarize, we will no longer consider
design changes or substantial editorial changes unless they relate to
severe security, interoperability or deployment problems. Furthermore, once
the RFCs are published, we'll move to the regular errata process - the RFC
editor pages contain more information about that [3].

This change does not affect other WG adopted documents in the repository.
They continue to be developed as is.

Best Regards
QUIC WG Chairs

[1] - https://github.com/quicwg/base-drafts
[2] -
https://github.com/quicwg/base-drafts/blob/master/CONTRIBUTING.md#post-iesg-process
[3] - https://www.rfc-editor.org/errata.php for more information