Modifications applied:

- python-unyt :: rephrase description, partly sourced and combined from
  <https://packages.debian.org/sid/python3-unyt>,
  <https://unyt.readthedocs.io/en/stable/>

- python-pyjanitor :: speed up tests with python-pytest-xdist (~x3
  faster on 16x threads), remove blank lines, disable exact tests
  related to PySpark.

Pushed as 370b79b4f5..cde0adaacd to master.

Thanks,
Oleg