[dovecot/core] d72603: README: Added missing supported RFCs

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: d72603a00f93638a9b7075dda2126b89b01a06b6
      https://github.com/dovecot/core/commit/d72603a00f93638a9b7075dda2126b89b01a06b6
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2016-05-09 (Mon, 09 May 2016)

  Changed paths:
    M README

  Log Message:
  -----------
  README: Added missing supported RFCs