add .pkgs argument to step_mutate()

[EmilHvitfeldt]

to close #1282

it is too much work for us to magically figure out what packages people use in step_mutate() so we ask them to do it

library(recipes)

rec <- recipe(~., data = mtcars) |>
  step_mutate(new = 2)

rec_pred <- rec |>
  prep()

required_pkgs(rec)
#> [1] "recipes"
required_pkgs(rec_pred)
#> [1] "recipes"


rec <- recipe(~., data = mtcars) |>
  step_mutate(new = 2, .pkgs = "stats")

rec_pred <- rec |>
  prep()

required_pkgs(rec)
#> [1] "recipes" "stats"
required_pkgs(rec_pred)
#> [1] "recipes" "stats"

^{Created on 2024-05-28 with reprex v2.1.0}

[simonpcouch]

🚀

[github-actions]

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