1.2.0

• Now requires Dart 3.
• BoardController can now take overlays and underlays as parameters, and passes them through to Board.
• BoardBuilder now takes a parameter forceSquareAlignment, which defaults to true, and forces elements to be aligned to their squares (previously this was not the case).
• SquareBuilder functions (such as those used by BoardBuilder) now return Widget?, i.e. they can return null. BoardBuilder will build an empty container in this case.
• BoardBuilder.index(): a BoardBuilder that uses an index, rather than rank and file.
• InputOverlay: an easy way to support common gestures like right clicks and long presses.
• SquareNumberOverlay: an overlay for debugging that shows the square index.
• LabelConfig is now exported correctly with the rest of the package.