Cabal revisions of HaTeX-3.1.0

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

 Name: HaTeX
 Version: 3.1.0+x-revision: 1
 Author: Daniel Díaz
 Category: Text
 Build-type: Simple
   Examples/fibs.hs  Library-  Build-depends: base ==4.*
+  Build-depends: base >= 4 && < 4.5
                , bytestring
                , mtl ==2.*
                , text