posterior 1.2.0

Enhancements

• support casting to/from rvar and distributional::dist_sample (#109)

Bug Fixes

• fix hidden variables in bind_draws.draws_df when binding
  more than two objects thanks to Jouni Helske (#204)
• fix output of pillar::glimpse() when used on a data frame containing
  rvars (#210)
• drop "draws" and "draws_df" classes from draws_df objects if meta data
  columns are removed by a dplyr operation (#202)
• fix output of print.draws_df() on objects with unrepaired draws (#217)
• ensure variance() works properly with summarise_draws() (#219)