Is this package deprecated? If so, is there a recommended strategy for migration to bslib?

[dvg-p4]

I suspect that this package is soft-deprecated entirely, given that it hasn't seen a commit in 3 years, and Posit's newer Shiny docs, e.g. the "get started" page and layout rundown now encourage the use of bslib in general and page_sidebar() in particular. If this is the intention, it might be a good idea to mention as such in this repo's README and on https://rstudio.github.io/shinydashboard/, and suggest moving to bslib for new projects.

Originally posted by @dvg-p4 in #408 (comment)