Update for copyright messages to 2024 (Happy New Year!) - Mailing list pgsql-hackers

Hi,
(CC-ing Bruce)

As of this new year, and in the vein of c8e1ba736b2b.  Bruce, are you
planning an update of the copyright dates with a run of
./src/tools/copyright.pl on HEAD, and the smallish updates of the back
branches?

And of course, Happy New Year to all!
--
Michael