node2nix: 1.6.0 -> 1.7.0 and regenerate all Nix expressions, introduce nodePackages_12_x attribute set

pkgs/development/node-packages/composition-v12.nix

@@ -0,0 +1,17 @@
+# This file has been generated by node2nix 1.7.0. Do not edit!
+
+{pkgs ? import <nixpkgs> {
+    inherit system;
+  }, system ? builtins.currentSystem, nodejs ? pkgs."nodejs-12_x"}:
+
+let
+  nodeEnv = import ./node-env.nix {
+    inherit (pkgs) stdenv python2 utillinux runCommand writeTextFile;
+    inherit nodejs;
+    libtool = if pkgs.stdenv.isDarwin then pkgs.darwin.cctools else null;
+  };
+in
+import ./node-packages-v12.nix {
+  inherit (pkgs) fetchurl fetchgit;
+  inherit nodeEnv;
+}