stringAsFactors warnings in R 4.2

[pat-s]

Saw this in R-devel mlr CI.

@berndbischl I think @jakob-r already fixed this in 8f9c97c. Would you mind pushing a new release to CRAN?

── Warning (test_base_tuning.R:54:3): tune ─────────────────────────────────────
'default.stringsAsFactors' is deprecated.
Use '`stringsAsFactors = FALSE`' instead.
See help("Deprecated")
Backtrace:
 1. base::as.data.frame(tr3$opt.path)
      at test_base_tuning.R:54:2
 2. ParamHelpers:::as.data.frame.OptPathDF(tr3$opt.path)
 6. BBmisc::convertListOfRowsToDataFrame(extra.clean)
 8. base::default.stringsAsFactors()
 9. base::.Deprecated("`stringsAsFactors = FALSE`")