fix: correct add-on slug

Resolves #33 by using the same slug as the add-on server.

And the same expected slug as the add-on page (window.location
when you click the add-on title in the installed add-ons screen):

"file:///Applications/Local.app/Contents/Resources/app.asar/renderer/_browserWindows/app/app.html#/main/marketplace/addon/instant-reload"

Author: nickcernis

package.json

@@ -8,7 +8,7 @@
   ],
   "bgColor": "#51bb7b",
   "icon": "icon.svg",
-  "slug": "local-addon-instant-reload",
+  "slug": "instant-reload",
   "description": "A Local addon that provides live browser reloading while developing WordPress sites.",
   "renderer": "lib/renderer.js",
   "main": "lib/main.js",