61623 Fix overflow issue caused by a long title/subtitle for the vertical stepper (cla: yes, f: material design, framework, waiting for tree to go green)

61648 Proposal: deprecate autovalidate parameter of the Form, FormField and TextFormField widget (cla: yes, f: material design, framework, waiting for tree to go green)

61662 add static method to create material hero controller (cla: yes, f: material design, framework, waiting for tree to go green)

61664 Add minWidth and height parameter into FlatButton widget (cla: yes, f: material design, framework, waiting for tree to go green)

61710 Added expandedHeight in flexibleSpace and flexibleSpaceBar (cla: yes, d: api docs, documentation, f: material design, framework, waiting for tree to go green)