Blacklist directory 1.2.3.0

This is to work around an issue with directory on older GHCs.

See haskell/directory#30

idris.cabal

@@ -900,7 +900,7 @@ Library
                 , cheapskate < 0.2
                 , containers >= 0.5 && < 0.6
                 , deepseq < 1.5
-                , directory >= 1.2.2.0 && < 1.3
+                , directory >= 1.2.2.0 && < 1.3 && /= 1.2.3.0
                 , filepath < 1.5
                 , fingertree >= 0.1 && < 0.2
                 , haskeline >= 0.7 && < 0.8