[packages/tzdata] (6 commits) Non-fast-forward update to branch dev-2020d

[glen]

The branch 'dev-2020d' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch.

Commits removed from the branch:

  ef882c0... Update tz data to 2020d

Commits added to the branch:

  316a7be... Update to build without base-0
  5ffa79e... Use single version macro
  cfa167f... Use single tzdb tarball (contains tzcode/tzdata, extras)
  411bc50... Up to 2020b
  cfabde9... Update to 2020c
  050dc00... Update to 2020d