Change start_url to './' in manifest.json

Updated start_url in manifest.json to point to the root directory.

Author: NellowTCS

Build/public/manifest.json

@@ -53,7 +53,7 @@
       "type": "image/png"
     }
   ],
-  "start_url": "/HTMLChat",
+  "start_url": "./",
   "display": "standalone",
   "background_color": "#00c6ff",
   "theme_color": "#00c6ff"