Add "include" to plugin.json

[shdwmtr]

Someone brought this plugin to my attention, so I added it to the plugin database (which will let your plugin to show up on the website)

In there I'm currently working on a build system, which right now only adds the .millennium, backend and other required folders into the build. include is a list of relative paths that tells the builder they are vital and need to be included in the final build. In your case, public, or whatever is needed. You can see in the build some important stuff is missing.

Don't worry about altering your current build system or removing it, this is just millennium specific stuff and wont interfere with anything :)

[BossSloth]

Oh nice, I was waiting for millennium 1.16.0 to release before adding it to plugdb. But this works too.
I added the include to the plugins.json and fixed webkit not building. Also opened a pr to update the submodule SteamClientHomebrew/PluginDatabase#4