rvinecopulib 0.5.0.1.0

Release following the updates of vinecopulib to 0.5.0, see
https://github.com/vinecopulib/vinecopulib/releases. The most
relevant changes are summarized below.

NEW FEATURES

• modelling discrete variables with bivariate or vine copulas. (#195)

• selection of partially specified R-vine structures. (#195)

• convenience classes dvine_structure()/cvine_structure() for D- and
  C-vine structures. (#195)

• new criterion for tree selection: "joe" corresponds to -log(1-r^2),
  where r is the pairwise partial correlation. (#195)

• random sampling of R-vine structures. (#197)

• add weights argument to vine(). (#188)

• parallelized fitting of margins in vine(). (#198)

API BREAK

• The new var_types argument for discrete models has been placed
  early in bicop()/vinecop() due to its importance. This might break old
  code calling these functions with unnamed arguments.

BUG FIXES AND OTHER IMPROVEMENTS

• better support for 0-truncated structures. (#195)

• ensure consistency of TLL likelihood during and after fit. (#195)

• fixed order of ranks in pseudo_obs(.., ties.method = "first"). (#195)

• safer computation of multivariate normal cdf. (#195)

• improved memory efficiency. (#195)