Stack offsets

[nickofthyme]

Is your feature request related to a problem? Please describe.
Enable stack offsets for wiggle and silhouette.

Silhouette
Shifts the baseline down such that the center of the streamgraph is always at zero.

Wiggle
Shifts the baseline so as to minimize the weighted wiggle of layers. This offset is recommended for streamgraphs in conjunction with the inside-out order. See Stacked Graphs—Geometry & Aesthetics by Bryon & Wattenberg for more information.

Additional context
Required for vislib feature parity

[markov00]

🎉 This issue has been resolved in version 21.0.0 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)

Your semantic-release bot 📦🚀