Tooltip labels don't work with D3 v6

[marcelomizuki]

Hi all,

Just be aware that the following issue can cause problems when using and compiling the source and using the
latest version of D3.

https://stackoverflow.com/questions/63693132/unable-to-get-node-datum-on-mouseover-in-d3-v6

Just wasted a couple of hours trying to figure out why the tooltip was producing: "undefined: undefined" and
it is because the first argument is the "event" and no longer the "datum" "d" in D3 V6. For now I just went back to
D3 V5.

[Saigesp]

Hi @marcelomizuki, thanks for the comment.

Yes, I haven't worked in this library for a long time (no free time). When I can I will update it to work with D3v6 and Vue3