dynamic_widget

[4.0.3] - add TextButton Widget and Card widget parser

• add TextButton widget parser, thanks ChangJoo Park(박창주)
• add Card widget parser, thanks linpc

[4.0.4] - add SingleChildScrollView widget parser and bugfix

• add add SingleChildScrollView widget parser
• bugfix

[3.0.4] - Fix bugs

• Fix the bug which photo can't be display in pub.dev

[3.0.5] - Add Scaffold and AppBar Widget

• Add Scaffold and AppBar Widget.
• Fix bugs.

[3.0.6] - bug fixed

• Fix the bug, https://github.com/dengyin2000/dynamic_widget/issues/64

[4.0.0-nullsafety.1] - null safety migration

• null safety migration

[4.0.0] - null safety migration

• null safety version released.

[4.0.1] - add ElevatedButtonParser

• add ElevatedButtonParser.

[4.0.2] - add DividerWidget and RotatedBox widget parser

• add DividerWidget and RotatedBox widget parser.

[3.0.3] - Fix bugs

• Fix some dart analysis problem.
• Preview page can export current page's flutter code to json.

Some PR merged, fix some bugs.