sim: replacing ChangeLog files with online git logs

[Andrew Burgess]

* Eli Zaretskii <eliz@gnu.org> [2021-03-24 18:46:38 +0200]:

> > Date: Tue, 23 Mar 2021 23:45:24 -0400
> > From: Mike Frysinger <vapier@gentoo.org>
> > Cc: gdb@sourceware.org, Andrew Burgess <andrew.burgess@embecosm.com>
> > 
> > Eli: those patches look OK to you too ?
> 
> They just add the script to our repository, AFAICT, so I of course
> have no objections.

No the second proposes to replace the current ChangeLog with one
auto-generated upon release.

This ChangeLog would in effect be a reformatted `git log` output.

For the simulator this would mean there would no longer be any file
that contained output in the format as:

	* file.c (symbol): description.

As Mike already does not include his ChangeLogs in the commit message
(as we do for the rest of gdb/, etc), and the motivation for this
change is to stop writing any text in that format, so likely future
sim/ contributions would not include text in that format either.

Thanks,
Andrew