Merge pull request #1539 from hvr/1.18

Relax build-dep to allow upcoming `array-0.5.0.0`

Cabal/Cabal.cabal

@@ -129,7 +129,7 @@ library
     process    >= 1.0.1.1 && < 1.3,
     time       >= 1.1     && < 1.5,
     containers >= 0.1     && < 0.6,
-    array      >= 0.1     && < 0.5,
+    array      >= 0.1     && < 0.6,
     pretty     >= 1       && < 1.2,
     bytestring >= 0.9