[BUG] Overflow when using flipped segmented axes

[oskgo]

Describe the bug Got panic thread 'main' panicked at 'attempt to subtract with overflow', [...]\plotters-0.3.2\src\coord\ranged1d\discrete.rs:148:56 when trying to draw a graph with discrete axes and flipped y-axis. I expected to get the same result as when not using discrete axes, except with the labels centered and possibly an off-by one error somewhere.

To Reproduce

let root = BitMapBackend::new("test.png", (1024, 1024)).into_drawing_area();

let mut chart = ChartBuilder::on(&root)
    .build_cartesian_2d((0..3).into_segmented(), (3..0).into_segmented())
    .unwrap();

chart
    .configure_mesh()
    .draw()
    .unwrap();

Version Information 0.3.2