Release v1.21.0

• Added: audeer.move()
  which can move files and folders
  and should be used instead of audeer.move_file()
• Added: *paths argument to
  audeer.mkdir(),
  audeer.rmdir(),
  and audeer.touch().
  Instead of writing audeer.mkdir(os.path.join('a', 'b')),
  you can now write audeer.mkdir('a', 'b')