posterior 1.5.0

Enhancements

• Added support for nested-Rhat via rhat_nested (#256)
• Added support for indexing draws in rvars using rvars (#282):
  • x[i] or x[i] <- y where i is a scalar logical rvar slices (or
    updates) x by its draws. Thus, if y <- x[i], then y is the same
    shape as x but with sum(i) draws.
  • x[[i]] or x[[i]] <- y where i is a scalar numeric rvar slices (or
    updates) x by selecting the ith element within each corresponding draw.
    Thus, if y <- x[[i]], then y is an rvar of length 1.
• Added rvar_ifelse(), which is a variant of ifelse() that accepts (and
  returns) rvars (#282).
• Array broadcasting for rvars has been made faster.

Bug Fixes

• Ensure rfun() works with primitive functions (#290) and dots arguments (#291).
• Provide implementations of vctrs::vec_proxy_equal(),
  vctrs::vec_proxy_compare(), and vctrs::vec_proxy_order().
• Minor future-proofing of cbind(<rvar>), rbind(<rvar>), and chol(<rvar>)
  for R 4.4 (#304).
• Ensure that bind_draws(<draws_rvars>) regenerates draw ids when binding along
  chains or draws; this also fixes a bug in split_chains(<draws_rvars>) (#300).