imagemagick: add erictapen as maintainer

pkgs/applications/graphics/ImageMagick/7.0.nix

@@ -84,6 +84,7 @@ stdenv.mkDerivation {
     homepage = "http://www.imagemagick.org/";
     description = "A software suite to create, edit, compose, or convert bitmap images";
     platforms = platforms.linux ++ platforms.darwin;
+    maintainers = with maintainers; [ erictapen ];
     license = licenses.asl20;
   };
 }