Adding a `variant` support for snapshots?

[danielinteractive]

Hello team,
first of all thanks for vdiffr- very important for the testing of plot functions.
One question - did you consider already adding variant support similar as shinytest2 e.g. has?
That could come in handy to save snapshots from different ggplot2 package versions e.g.

[lionel-]

yes in fact part of the motivation for adding a variant mechanism in testthat was to support multiple svg snapshots for different R versions..

[lionel-]

Now on CRAN!