haven 2.4.2

• Updated to ReadStat 1.1.7 RC (#620).

• read_dta() no longer crashes if it sees StrL variables with missing values
  (@gorcha, #594, #600, #608).
  urlchecker::url_check()

• write_dta() now correctly handles "labelled"-class numeric (double) variables
  that don't have value labels (@jmobrien, #606, #609).

• write_dta() now allows variable names up to 32 characters (@sbae, #605).

• Can now correctly combine labelled_spss() with identical labels
  (@gorcha, #599).