treewide: remove the-kenny from maintainers

@the-kenny did a good job in the past and is set as maintainer in many package,
however since 2017-2018 he stopped contributing. To create less confusion
in pull requests when people try to request his feedback, I removed him as
maintainer from all packages.

pkgs/applications/misc/slic3r/default.nix

@@ -85,6 +85,6 @@ stdenv.mkDerivation rec {
     homepage = "https://slic3r.org/";
     license = licenses.agpl3;
     platforms = platforms.linux;
-    maintainers = with maintainers; [ bjornfor the-kenny ];
+    maintainers = with maintainers; [ bjornfor ];
   };
 }