[<Axis>] axisLineProps attribute

[valtism]

I was trying to add rounded linecaps on all my lines in a chart, but I realised that although I could do it on an for the tick line with tickLineProps, there is no corresponding property axisLineProps and I am unable to round the line caps for the main axis line.

I think something like an axisLineProps attribute would be expected here.

[williaster]

Hey @valtism 👋 ah good catch on this. You could still control is via css with .visx-axis-line as a workaround, but I agree it might be worth adding axisLineProps as a catchall for SVG line element props (some are already there like stroke and strokeDasharray, but rather than adding more we could add an object prop).

Happy to review a PR if anyone is interested! Can convert this to an issue to track as well.