Upgrade stokes to 21.05

clusters/stokes/kernel.nix

@@ -1,4 +1,4 @@
-{pkgs, stdenv, fetchurl, config, kernel ? pkgs.linux, ...}:
+{pkgs, lib, stdenv, fetchurl, config, kernel ? pkgs.linux, ...}:
 let
   i40e =
     stdenv.mkDerivation rec {
@@ -33,14 +33,14 @@ let
       meta = {
         description = "Linux kernel drivers for Intel Ethernet adapters and LOMs (LAN On Motherboard)";
         homepage = https://github.com/dmarion/i40e;
-        license = stdenv.lib.licenses.gpl2;
+        license = lib.licenses.gpl2;
       };
     };
 in
 {
   i40e2 = i40e;
   overlay = self: super: {
-    linuxPackages = super.linuxPackages // { inherit i40e; };
+    linuxPackages_5_4 = super.linuxPackages_5_4 // { inherit i40e; };
   };
 }