Relax upper bound to allow `time-1.5`

unix.cabal

@@ -60,7 +60,7 @@ library
     build-depends:
         base        >= 4.5     && < 4.9,
         bytestring  >= 0.9.2   && < 0.11,
-        time        >= 1.2     && < 1.5
+        time        >= 1.2     && < 1.6
 
     exposed-modules:
         System.Posix