Issue 805/PR 808, empty case when broadcasting UnionArrays.
1.2.3
Same as [1.3.0rc4](https://github.com/scikit-hep/awkward-1.0/releases/tag/1.3.0rc4). Deploying as a full release because issue #859 was encountered twice (before as 836), so it's a common problem.
1.2.2
Like 1.3.0rc3, but also fixes issue 819: PR 820.
See release notes for 1.3.0rc1, 1.3.0rc2, 1.3.0rc3. This release comes _after_ those.
1.2.1
ianna fixed the data type of `ak.argsort` for empty arrays (it should always be integer, but was float in some cases). PR 803.