Start of Emacs 30 release cycle

[Eli Zaretskii <eliz@gnu.org>]

Hi,

I've created the emacs-30 release branch, which will be used to
release the Emacs 30.x series.  Changes installed on this branch
should be bugfixes that do not modify too low-level code, and thus
don't risk destabilizing the codebase we have on that branch now.  All
the other changes, including new features, should be installed on
master, as usual.  If in doubt whether a particular change should be
installed on master or on the release branch, please ask here.

Please build the emacs-30 branch on your system and with your
configuration options, and report any problems you see (via "M-x
report-emacs-bug").

I hope to make the first pretest of Emacs 30.1 in about a month from
now.

Thanks.