Remove includes from .cabal-file

This is useless at best, and a common source of confusion.

haskell/cabal#10145
sol/hpack#355

Author: sol

bzlib.cabal

@@ -36,7 +36,6 @@ library
                    bytestring >= 0.9 && < 0.13
   if os(windows)
     build-depends: base >= 4.11
-  includes:        bzlib.h
   ghc-options:     -Wall
   if !(os(windows) || impl(ghcjs) || os(ghcjs) || arch(wasm32))
     -- Normally we use the the standard system bz2 lib: