Warning after Upgrade to Flutter 3

[BenPoell]

: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
../…/lib/boardview.dart:307
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
      WidgetsBinding.instance!.addPostFrameCallback((Duration duration) {
                     ^

: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
../…/lib/boardview.dart:569
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
      WidgetsBinding.instance!.addPostFrameCallback((timeStamp) {
                     ^

: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
../…/lib/board_item.dart:92
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
    WidgetsBinding.instance!

                   ^
: Warning: Operand of null-aware operation '?.' has type 'SchedulerBinding' which excludes null.
../…/lib/table_sticky_headers.dart:115
- 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../../flutter/packages/flutter/lib/src/scheduler/binding.dart').
package:flutter/…/scheduler/binding.dart:1
    SchedulerBinding.instance?.addPostFrameCallback((_) {