FreeBSD CI: perform CI test on 12 and 11
FreeBSD_task:
+ matrix:
freebsd_instance:
image: freebsd-12-1-release-amd64
+ freebsd_instance:
+ image: freebsd-11-3-stable-amd64-v20191205
env:
ASSUME_ALWAYS_YES: TRUE # required for unattanded "pkg" invocation
prepare_script:
