Forgot entry in .cabal

Author: harpocrates

haddock-api/haddock-api.cabal

@@ -166,7 +166,8 @@ test-suite spec
     Haddock.Backends.Hyperlinker.Parser
     Haddock.Backends.Hyperlinker.Types
 
-  build-depends: ghc             ^>= 8.2
+  build-depends: Cabal           ^>= 2.0.0
+               , ghc             ^>= 8.2
                , ghc-paths       ^>= 0.1.0.9
                , haddock-library ^>= 1.4.6
                , xhtml           ^>= 3000.2.2