Use dev-lang/GHC instead of dev-lang/ghc-bin

sets/development.conf

@@ -5,9 +5,8 @@
 
 # haskell
 * haskell-platform
-* dev-lang/ghc-bin:8.4.3
-* dev-lang/ghc-bin:8.2.2
-* dev-lang/ghc-bin:8.0.2
+* dev-lang/GHC:8.2.2
+* dev-lang/GHC:8.4.3
 
 # VCSes and VCS-tools
 * dev-scm/mercurial