haskell-defaults.nix: build 'entropy' with a recent version of Cabal on older platforms

Changed files
+1
pkgs
+1
pkgs/top-level/haskell-defaults.nix
···
vectorBinaryInstances = self.vectorBinaryInstances.override { binary = self.binary_0_7_2_2; };
};
};
+
entropy = super.entropy.override { cabal = self.cabal.override { Cabal = self.Cabal_1_18_1_3; }; };
gloss = null; # requires base >= 4.7
haddock = self.haddock_2_13_2;
modularArithmetic = null; # requires base >= 4.7