Add support for forwardRef to allow exporting of images, (Sankey chart)

[kfaiczak]

Would really like the forwardRef supported for ResponsiveSankey chart (and others that use the ResponsiveWrapper

I see this issue has been raised a few times, but keeps becoming stale and closed.

This would allow the chart to be exported in various ways .. png, pdf, 64bit uuencoded etc ... by various other libraries
In particular I am thinking of using react-component-export-image. to export the image using the ref