nix/versions bump default versions with new nixpkgs/master

nix/default.nix

@@ -22,6 +22,7 @@
         [ "nixos" (mkChannelSource "channelsNixosStable" + "/nixos") ]
         [ "channels-nixos-stable" (mkChannelSource "channelsNixosStable") ]
         [ "channels-nixos-unstable" (mkChannelSource "channelsNixosUnstable") ]
+        [ "nixpkgs-master" (mkChannelSource "nixpkgsMaster") ]
         [ "home-manager-module" (mkChannelSource "homeManagerModule") ]
       ];
     in (import (mkChannelSource "channelsNixosStable") {}).writeText "channels.rc" ''

nix/variables/versions.nix

@@ -1,15 +1,20 @@
 {
   channelsNixosStable = {
-    ref = "nixos-18.09";
-    rev = "7e88992a8c7b2de0bcb89182d8686b27bd93e46a";
+    ref = "nixos-19.03";
+    rev = "3a4ffdd38b56801ce616aa08791121d36769e884";
   };
   channelsNixosUnstable = {
     ref = "nixos-unstable";
-    rev = "44b02b52ea6a49674f124f50009299f192ed78bb";
+    rev = "07b42ccf2de451342982b550657636d891c4ba35";
+  };
+  nixpkgsMaster = {
+    url = "https://github.com/NixOS/nixpkgs/";
+    ref = "master";
+    rev = "d8c7f0bd3f42bc9e687b12ce7f0a4ef747f27933";
   };
   homeManagerModule = {
-    url = "https://github.com/rycee/home-manager/";
-    ref = "release-18.09";
-    rev = "dd94a849df69fe62fe2cb23a74c2b9330f1189ed";
+    url = "https://github.com/rycee/home-manager";
+    ref = "master";
+    rev = "03162970cd6dadfac58f169cd50aed5a5aeec14f";
   };
 }

nix/variables/versions.tmpl.nix

@@ -7,6 +7,11 @@
     ref = "nixos-unstable";
     rev = "<% git ls-remote https://github.com/nixos/nixpkgs-channels nixos-unstable | awk '{ print $1 }' | tr -d '\n' -%>";
   };
+  nixpkgsMaster = {
+    url = "https://github.com/NixOS/nixpkgs/";
+    ref = "master";
+    rev = "<% git ls-remote https://github.com/NixOS/nixpkgs.git master | head -n1 | awk '{ print $1 }' | tr -d '\n' -%>";
+  };
   homeManagerModule = {
     url = "https://github.com/rycee/home-manager";
     ref = "master";