Update readme to cater for android 12

[J-LunZA]

Starting in Android 12 (API level 31), a generic web intent resolves to an activity in your app only if your app is approved for the specific domain contained in that web intent. If your app isn't approved for the domain, the web intent resolves to the user's default browser app instead.

a detailed explanation can be found here:

https://doordash.engineering/2022/01/25/your-deep-links-might-be-broken-web-intents-and-android-12/