contrib: move the MinGW download location to mercurial-scm.org
(Don't bother with Windows CI on this, since this script is only manually run)
All legacy (hg-git based) Projects have been automatically migrated to native with the upgrade of 2025-01-23
This instance will be upgraded to Heptapod 17.7.1 on 2025-02-13 between 18:00 and 19:00 UTC+2
(Don't bother with Windows CI on this, since this script is only manually run)