add 'arrowShape' prop

[valerii-starlight]

Is your feature request related to a problem? Please describe. I would love to achieve something like this:

Current customization options do not allow for a similarly smooth arrow.

Describe the solution you'd like Thinking something like: arrowShape = 'sharp' | 'smooth'

[AdamGerthel]

The project is not actively developed, but we definitely accept PR's. I think the best solution here would be to be able to pass a custom component as an alternative to the Arrow component.