devtools v2.1.0

New Features

• testthat and roxygen2 are now added to Imports rather than Suggests,
  so they are automatically installed when you install devtools.

Deprecated functions now removed

• create(), create_description(), setup()
use_appveyor(), use_build_ignore(), use_code_of_conduct(),
  use_coverage(), use_cran_badge(), use_cran_comments(), use_data(),
  use_data_raw(), use_dev_version(), use_git(), use_git_hook(),
  use_github(), use_github_links(), use_gpl3_license(),
  use_mit_license(), use_news_md(), use_package(), use_package_doc(),
  use_rcpp(), use_readme_md(), use_readme_rmd(), use_revdep(),
  use_rstudio(), use_test(), use_testthat(), use_travis(),
  use_vignette(), have been removed after being deprecated in previous
  releases. Use the versions in the usethis
  package directly.

• check_cran(), revdep_check(), revdep_check_print_problems(),
  revdep_check_reset(), revdep_check_resume(), revdep_check_save_summary(),
  revdep_email() have been removed after being
  deprecated in prevous releases. It is recommended to use the
  revdepcheck package instead.

• system_check(), system_output() have been removed after being deprecated
  in previous releases. It is recommend to use the
  processx package instead.

• build_win() has been removed, after being deprecated in previous releases.

• yesno() as used in release() now has clearer synonyms for "yes" (@mattmalin, #1993)

Minor improvements and fixes

• check_rhub gains a new argument build_args for arguments passed to
  R CMD build. ... is now passed to rhub::check_for_cran() (@gaborcsardi, @maelle, #2041)

• build_manual() now fails if the manual fails to build. (#2056)

• test_file() and test_coverage_file() now work with C
  and C++ files in the src/ directory as well.