Cabal revisions of purescript-0.6.8

Hackage metadata revisions edit the .cabal file after upload; each diff below is one revision.

 name: purescript version: 0.6.8+x-revision: 1 cabal-version: >=1.8 build-type: Simple license: MIT     location: https://github.com/purescript/purescript.git  library-    build-depends: base >=4.6 && <5,+    build-depends: base >=4.6 && <4.8,                    containers -any,                    unordered-containers -any,                    directory >= 1.2,