Allow random-1.2 and QuickCheck-2.14

[Bodigrim]

This is a conservative approach to unblock random-1.2, cf. #53.

Tested with

packages: uuid-types/
          uuid/

tests: True

constraints:
  random >= 1.2

random-1.2 has been already allowed by a Hackage revision for uuid-types only.

[phadej]

I relaxed bounds in #56, thanks anyway.