readr 2.1.0

• All readr functions again read eagerly by default. Unfortunately many users
  experienced frustration from the drawbacks of lazy reading, in particular
  locking files on Windows, so it was decided to disable lazy reading default.
  However options(readr.read_lazy = TRUE) can be used to set the default to by lazy if desired.
• New readr.read_lazy global option to control if readr reads files lazily or not (#1266)