Remove StoreEffects.

In its current incarnation it is never used, we will resurrect a much
simpler pared-down version based on hnix's actual needs later.

Author: shlevy

hnix-store-core/hnix-store-core.cabal

@@ -1,5 +1,5 @@
 name:                hnix-store-core
-version:             0.1.1.0
+version:             0.2.0.0
 synopsis:            Core effects for interacting with the Nix store.
 description:
         This package contains types and functions needed to describe
@@ -27,7 +27,6 @@ library
                      , System.Nix.Nar
                      , System.Nix.Path
                      , System.Nix.ReadonlyStore
-                     , System.Nix.Store
                      , System.Nix.StorePath
                      , System.Nix.Util
   build-depends:       base >=4.10 && <5