Docs: Updated the homepage link. [skip ci]

Author: Reinmar

package.json

@@ -63,7 +63,7 @@
   },
   "author": "CKSource (http://cksource.com/)",
   "license": "GPL-2.0-or-later",
-  "homepage": "https://ckeditor.com",
+  "homepage": "https://ckeditor.com/ckeditor-5",
   "bugs": "https://github.com/ckeditor/ckeditor5-build-classic/issues",
   "repository": {
     "type": "git",