ci: Upgrade MacPorts version to 2.10.1.
MacPorts version 2.9.3 started failing in our ci_macports_packages.sh
script, for reasons not fully determined, but plausibly linked to the
release of 2.10.1. 2.10.1 seems to work, so let's switch to it.
Back-patch to 15, where CI began.
Reported-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/
81f104e8-f0a9-43c0-85bd-
2bbbf590a5b8%40eisentraut.org