import upstream tarball postgresql-common_147.pgdg12.4+1
Merge branch 'upstream' into bp/precise

Conflicts:
	debian/changelog
import upstream tarball postgresql-common_150.pgdg12.4+1
merge upstream tarball postgresql-common_150.pgdg12.4+1
hardcode 9.1 and 9.3 versions
downgrade standards-version to 3.9.3