Migrate to 3.0.0

[M2dL1fe]

../../flutter/.pub-cache/hosted/pub.flutter-io.cn/sticky_and_expandable_list-1.0.3/lib/src/expandable_section_container.dart:170:22: Warning: Operand of null-aware operation '?.' has type 'WidgetsBinding' which excludes null.

• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../flutter/packages/flutter/lib/src/widgets/binding.dart').
  WidgetsBinding.instance?.addPostFrameCallback((timeStamp) {
  ^
  ../../flutter/.pub-cache/hosted/pub.flutter-io.cn/sticky_and_expandable_list-1.0.3/lib/src/sliver_expandable_list.dart:410:22: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../flutter/packages/flutter/lib/src/widgets/binding.dart').
  WidgetsBinding.instance!.addPostFrameCallback((_) {
  ^

[tp7309]

done, try 1.1.0 version.

[M2dL1fe]

nice @tp7309

[fullflash]

same error with lates version.

[        ] ../../../../.pub-cache/hosted/pub.dartlang.org/sticky_and_expandable_list-1.1.0/lib/src/expandable_section_container.dart:170:31: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
../…/src/expandable_section_container.dart:170
[        ]  - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../../SDK_all/flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
[        ] Try calling using ?. instead.
[        ]       WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
[        ]                               ^^^^^^^^^^^^^^^^^^^^

[tp7309]

@fullflash see #43.