mlr3 0.7.0

• Updated properties of featureless learners to apply it on all feature types
  (did not work on POSIXct columns).
• Fixed measures being calculated as NaN for BenchmarkResult for resamplings
  with a single iteration (#551).
• Fixed a bug where a broken heuristic disabled nested parallelization via
  package future (mlr3tuning#270).
• ResampleResult and BenchmarkResult now share a common interface to store
  the experiment results. Manual construction is still possible with helper
  function as_result_data()
• Fixed deep cloning of ResamplingCV and ResamplingRepeatedCV.
• New measure classif.prauc (area under precision-recall curve).
• Removed dependency on orphaned package bibtex.