* The patches for `barbies`, `ghc-tcplugins-extra`, `ghc-typelits-extra`,
  `mono-traversable`, and `persistent-sqlite` have all been dropped as
  their latest Hackage versions support GHC 8.8 through HEAD.
* The `pandoc-2.9.1` patch has been migrated to support the latest
  Hackage version, 2.9.1.1.