Reminder: update py39cloud branch with next release

[jdblischak]

Note to self: with the next release of TileDB-SOMA, we need to update main as well as the branch py39cloud

We will only need to maintain the separate py39cloud branch for as long as we continue to maintain the py39 TileDB Cloud env. Hopefully the transition to py312 will not be protracted (and thus it's not worth updating our release guidelines)

cc: @johnkerl