pkgdepends 0.8.0

• pkgdepends now supports gitlab:: package sources better, by adding
  explicit syntax to specify subdirectories (#353, @dgkf).

• gitlab:: and git:: package sources now support git submodules if
  the git-submodules configuration option is set to TRUE. See
  ?"pkgdepends-config" (#354).

• The new ?ignore-unavailable parameter makes it easy to ignore soft
  dependencies that are unavailable
  (r-lib/pak#606).

• pkgdepends now automatically ignores soft dependencies that have an
  incompatible OS type (OS_type entry in DESCRIPTION) when installing
  packages.