Relax attoparsec constraint

Author: John Wiegley

github.cabal

@@ -141,7 +141,7 @@ Library
  Build-depends: base >= 4.0 && < 5.0,
  time,
  aeson == 0.6.1.0,
- attoparsec == 0.10.3.0,
+ attoparsec >= 0.10.3.0,
  bytestring,
  containers,
  text,