Update parallelism

[hfrick]

In the spirit of #124, let's act on our own deprecation warnings 🧹

 4. LDA parallel test ('test-parallel-psock.R:22:3') - ! tune detected a parallel backend registered with foreach but no backend registered with future.
  i Support for parallel processing with foreach was soft-deprecated in tune 1.2.1.
  i See ?parallelism (`?tune::parallelism()`) to learn more.
  
  5. recipe-adjacent parallel test ('test-parallel-psock.R:47:3') - ! tune detected a parallel backend registered with foreach but no backend registered with future.
  i Support for parallel processing with foreach was soft-deprecated in tune 1.2.1.
  i See ?parallelism (`?tune::parallelism()`) to learn more.
  
  6. parallel seeds ('test-parallel-seeds.R:22:3') - ! tune detected a parallel backend registered with foreach but no backend registered with future.
  i Support for parallel processing with foreach was soft-deprecated in tune 1.2.1.
  i See ?parallelism (`?tune::parallelism()`) to learn more.
  
  7. parallel seeds ('test-parallel-seeds.R:26:3') - ! tune detected a parallel backend registered with foreach but no backend registered with future.
  i Support for parallel processing with foreach was soft-deprecated in tune 1.2.1.
  i See ?parallelism (`?tune::parallelism()`) to learn more.