Deprecate ggdep

[hadley]

Since once #3380 is merged it will no longer be used, and it doesn't align with the latest tidyverse standards for deprecated.

Part of #3057

[paleolimbot]

This is brief advice, but I think following it is a reasonable way to deprecate gg_dep(): tidyverse/design#72

[lock]

This old issue has been automatically locked. If you believe you have found a related problem, please file a new issue (with reprex) and link to this issue. https://reprex.tidyverse.org/