below is the issue when running the app in flutter 3.0+
`/opt/homebrew/Caskroom/flutter/2.8.1/flutter/.pub-cache/hosted/pub.dartlang.org/scratcher-2.2.0/lib/widgets.dart:180:44: Warning: Operand of null-aware operation '?.' has type 'WidgetsBinding' which excludes null.
'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/opt/homebrew/Caskroom/flutter/2.8.1/flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
WidgetsBinding.instance?.addPostFrameCallback((_) {`
below is the issue when running the app in flutter 3.0+
`/opt/homebrew/Caskroom/flutter/2.8.1/flutter/.pub-cache/hosted/pub.dartlang.org/scratcher-2.2.0/lib/widgets.dart:180:44: Warning: Operand of null-aware operation '?.' has type 'WidgetsBinding' which excludes null.