Here is easier way to add Edgegap's hosting, or any package, directly from Unity’s editor. The Git Package manager method.

First, download a Git package manager, such as Git SCM

While it runs, in the Unity editor, select "Window", then "Package Manager", click on the "+" button and select "Add Package from git URL". Type the GIT URL such as https://github.com/edgegap/edgegap-unity-plugin.git

Click "Add", and the package will automatically download and added to your project!