Install latest rsync on macOS builder

[jwodder]

Closes #218.

[jwodder]

Due to data protection policies, I wasn't able to run the rsync command bundled in the DMG built for this PR (at least, not without installing git-annex from the DMG, which I didn't want to do), but running strings rsync did indicate that the version was at least 3.2.0 and was likely 3.3.0 (the version currently on Homebrew).

[yarikoptic]

I did yoh@datalads-imac2 datalad-installer % src/datalad_installer.py git-annex -m datalad/git-annex on that mac laptop we have for development (since I do not remember all the dances to do with .dmg from cli to install it). It seems to install newish git-annex but bundled rsync seems to be old... may be it is a prior build from master? will try tomorrow again

yoh@datalads-imac2 datalad-installer % find /Applications/git-annex.app/Contents/MacOS/ | grep rsync
/Applications/git-annex.app/Contents/MacOS//bundle/rsync
yoh@datalads-imac2 datalad-installer % /Applications/git-annex.app/Contents/MacOS//bundle/rsync --version
rsync  version 2.6.9  protocol version 29
Copyright (C) 1996-2006 by Andrew Tridgell, Wayne Davison, and others.
<http://rsync.samba.org/>
Capabilities: 64-bit files, socketpairs, hard links, symlinks, batchfiles,
              inplace, IPv6, 64-bit system inums, 64-bit internal inums

rsync comes with ABSOLUTELY NO WARRANTY.  This is free software, and you
are welcome to redistribute it under certain conditions.  See the GNU
General Public Licence for details.
yoh@datalads-imac2 datalad-installer % /Applications/git-annex.app/Contents/MacOS/git-annex version --raw
10.20250115-g7a8bc19228b2e16ec86836277c4077b63667b391

[yarikoptic]

yeay -- with a fresh rerun -- we are all good

yoh@datalads-imac2 datalad-installer % /Applications/git-annex.app/Contents/MacOS/git-annex version --raw
10.20250115-g84cd1668053e13e31f2ffaf4ddfd54e11d536637%                                                                                                                              yoh@datalads-imac2 datalad-installer % /Applications/git-annex.app/Contents/MacOS//bundle/rsync --version
rsync  version 3.3.0  protocol version 31
Copyright (C) 1996-2024 by Andrew Tridgell, Wayne Davison, and others.