Deprecated usage of aes_string() from {ggplot2}

[fkohrt]

When using qacBase::crosstab(), I get a deprecation error. For example, when running the following code:

withr::with_options(list(lifecycle_verbosity = "error",
                         warn = 2), {
  qacBase::crosstab(qacBase::cars74, cyl, gear, plot=TRUE)
})

I get the following error:

Error:
! `aes_string()` was deprecated in ggplot2
  3.0.0.
ℹ Please use tidy evaluation ideoms with `aes()`
---
Backtrace:
  1. withr::with_options(...)
  3. qacBase::crosstab(qacBase::cars74, cyl, gear, plot = TRUE)
  5. qacBase:::plot.crosstab(results)
  8. ggplot2::aes_string(x = rowvar, y = "Freq", fill = colvar)
  9. ggplot2:::deprecate_soft0("3.0.0", "aes_string()", details = "Please use tidy evaluation ideoms with `aes()`")
 10. lifecycle::deprecate_soft(..., user_env = user_env)
 11. lifecycle:::deprecate_stop0(msg)
Run `rlang::last_trace()` to see the full context.

Same for qacBase::cor_plot():

withr::with_options(list(lifecycle_verbosity = "error",
                         warn = 2), {
  qacBase::cor_plot(attitude)
})