Rolling alpha to 0.0.20 (flutter#13511)

Release 0.0.19 (flutter#13365)

Add EdgeInsets, MediaQuery support for view insets (flutter#13272)

* Add MediaQuery support for view insets

Also updates EdgeInsets documentation to reflect WindowPadding's use for
both padding and view insets.

See engine commits:
  flutter/engine#4403
  flutter/engine#4406

release 0.0.17 (flutter#12590)

Version 0.0.16 (flutter#12488)

Release 0.0.15 (flutter#12056)

Roll alpha (flutter#11874)

Wrap the label widget of the Chip in a Flexible. (flutter#11523) (flu…

…tter#11554)

* Wrap the label widget of the Chip in a Flexible. (flutter#11523)

* This allows the Chip to constrain the size of its content after taking into account the space occupied by the avatar and delete icon (if they are present)

* Adding unit tests to evaluate correct size constraints of the Chip widget's label. (flutter#11523)

* Minor change in formatting.

* Adjust function formatting.

prepare alpha release (flutter#11464)

Update versions for an alpha release (flutter#10896)