ceptre: switch to fetchFromGitHub

pkgs/development/interpreters/ceptre/default.nix

···
-{ lib, stdenv, fetchgit, mlton }:
+{ lib, stdenv, fetchFromGitHub, mlton }:
 
 stdenv.mkDerivation {
   pname = "ceptre";
   version = "unstable-2016-11-27";
 
-  src = fetchgit {
-    url = "https://github.com/chrisamaphone/interactive-lp";
+  src = fetchFromGitHub {
+    owner = "chrisamaphone";
+    repo = "interactive-lp";
     rev = "e436fda2ccd44e9c9d226feced9d204311deacf5";
-    sha256 = "174pxfnw3qyn2w8qxmx45fa68iddf106mkfi0kcmyqxzsc9jprh8";
+    sha256 = "sha256-COYrE9O/Y1/ZBNHNakBwrUVklCuk144RF9bjwa3rl5w=";
+    fetchSubmodules = true;
   };
 
   nativeBuildInputs = [ mlton ];