The release notes promise improved support for Xcode 12 and for Apple silicon.

Previous update: to 3.18.2 in #30150

CC: @jhpalmieri @slel @kiwifb @zlscherr

Component: packages: optional

Author: Matthias Koeppe

Branch/Commit: 982e4a3

Reviewer: John Palmieri

Issue created by migration from https://trac.sagemath.org/ticket/31258