Remove unused -XCPP from Client.ProjectPlanning

Author: philderbeast

cabal-install/src/Distribution/Client/ProjectPlanning.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE LambdaCase #-}