staging: accept nomad bsl license

cluster/staging/cluster.nix

@@ -101,6 +101,7 @@
 
   # Test nomad 1.6
   services.nomad.package = lib.mkForce pkgs.nomad_1_6;
+  nixpkgs.config.allowUnfree = true; # Accept nomad's BSL license
 
   # We're doing lots of experiments so GC periodically is usefull.
   nix.gc.automatic = true;