pythonPackages.jupyter: set priority

in order to prevent a collision.

pkgs/top-level/python-packages.nix

@@ -8160,6 +8160,7 @@ in {
       homepage = "http://jupyter.org/";
       license = licenses.bsd3;
       platforms = platforms.all;
+      priority = 100; # This is a metapackage which is unimportant
     };
   };