Increase hashable upper bound

snap-core.cabal

@@ -151,7 +151,7 @@ Library
     filepath                  >= 1.1     && < 2,
     lifted-base               >= 0.1     && < 0.3,
     io-streams                >= 1.3     && < 1.6,
-    hashable                  >= 1.2.0.6 && < 1.5,
+    hashable                  >= 1.2.0.6 && < 2,
     monad-control             >= 1.0     && < 1.1,
     mtl                       >= 2.0     && < 2.4,
     random                    >= 1       && < 2,