Migrate to version 0.55.0

The ability to rotate the RadarChart titles #1057

We added the ability to customize the rotation angles of the RadarChart titles.
To do that we had to break one thing and added a new type.

Breaking:

We only changed RadarChartData.getTitle. Its type [GetTitleByIndexFunction] changed from string Function(int index) to RadarChartTitle Function(int index, double angle).

To reuse the example from the code:

Previously:

getTitle: (index) {
  switch (index) {
    case 0:
      return 'Mobile or Tablet';
    case 2:
      return 'Desktop';
    case 1:
      return 'TV';
    default:
      return '';
  }
}

Now in new version:

getTitle: (index, angle) {
  switch (index) {
    case 0:
      return RadarChartTitle(text: 'Mobile or Tablet', angle: angle);
    case 2:
      return RadarChartTitle(text: 'Desktop', angle: angle);
    case 1:
      return RadarChartTitle(text: 'TV', angle: angle);
    default:
      return const RadarChartTitle(text: '');
  }
}

If you take the provided angle and forward it to the [RadarChartTitle] it will behave like in previous versions. But you can now render all the titles horizontally by avoiding the [RadarChartTitle.angle] prop (0 by default).

Apply a relative angle, for example: RadarChartTitle(text: 'Desktop', angle: angle + 90);

or an absolute angle, for example: RadarChartTitle(text: 'Desktop', angle: 90);