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/development/tools/build-managers/leiningen/default.nix

@@ -48,6 +48,5 @@ stdenv.mkDerivation rec {
     description = "Project automation for Clojure";
     license = stdenv.lib.licenses.epl10;
     platforms = stdenv.lib.platforms.linux ++ stdenv.lib.platforms.darwin;
-    maintainers = with stdenv.lib.maintainers; [ the-kenny ];
   };
 }

pkgs/development/tools/build-managers/rebar/default.nix

@@ -36,7 +36,6 @@ stdenv.mkDerivation {
       '';
 
     platforms = stdenv.lib.platforms.unix;
-    maintainers = [ stdenv.lib.maintainers.the-kenny ];
     license = stdenv.lib.licenses.asl20;
   };
 }