Integrating wicket with leaflet widget drupal 8

I am trying to get leaflet widget working properly in Drupal 8. I have been following the guidelines for installing wicket at here on the leaflet widget for geofield module.

I have installed the wicket libraries at app/web/libraries/wicket - snapshot of file structure attached below

I put the code snippet into my composer.json file (copy of file added below). when I run hte command " composer require arthur-e/Wicket" then I get the following message:

quote
$ composer require arthur-e/Wicket

[InvalidArgumentException]
Could not find package arthur-e/Wicket.

Did you mean this?
drupal/leaflet_widget

unquote

Needless to say, I am a newbie to drupal and not really a coder, so any help would be much appreciated!