drawGaugeScale method
Draws the main scale of the Gauge
Implementation
void drawGaugeScale(Canvas canvas, Size size) {
final Offset endPoint = Offset(size.width / 2, getScaleUpperLimit(size));
final Offset startPoint = Offset(size.width / 2, getScaleLowerLimit(size));
final gaugeScalePainter = Paint()
..color = Colors.grey.shade300
..strokeWidth = gaugeStrokeWidth;
canvas.drawLine(startPoint, endPoint, gaugeScalePainter);
}