databases/postgis30: Mark BROKEN

PostGIS 3.0.x only supports PostgreSQL 11 to 14 but the default pgsql has been
changed to 15 in 0c0bf56482b394740f5c14326ae1586158813129.

pkg-static: postgresql15-client-15.4 conflicts with postgresql11-client-11.21 (installs files into the same place). Problematic file: /usr/local/bin/clusterdb

Approved by: portmgr (blanket)
Reference: https://pkg-status.freebsd.org/beefy18/data/main-amd64-default/p30045eaacebe_s3fb80f1476/logs/postgis30-3.0.9.log

		https://pkg-status.freebsd.org/beefy12/data/140releng-amd64-default/e88d010d0a2b/logs/postgis30-3.0.9.log
		https://pkg-status.freebsd.org/beefy16/data/132amd64-default/30045eaacebe/logs/postgis30-3.0.9.log
		https://pkg-status.freebsd.org/beefy6/data/124amd64-default/d89d8cab6aaa/logs/postgis30-3.0.9.log