Mark jupyter_client=6.1.13 as broken

[davidbrochart]

Guidelines for marking packages as broken:

• We prefer to patch the repo data (see here)
  instead of marking packages as broken. This alternative workflow makes environments more reproducible.
• Packages with requirements/metadata that are too strict but otherwise work are
  not technically broken and should not be marked as such.
• Packages with missing metadata can be marked as broken on a temporary basis
  but should be patched in the repo data and be marked unbroken later.
• In some cases where the number of users of a package is small or it is used by
  the maintainers only, we can allow packages to be marked broken more liberally.
• We (conda-forge/core) try to make a decision on these requests within 24 hours.

Checklist:

• Make sure your package is in the right spot (broken/* for adding the
  broken label, not_broken/* for removing the broken label, or token_reset/*
  for token resets)
• Added a description of the problem with the package in the PR description.
• Added links to any relevant issues/PRs in the PR description.
• Pinged the team for the package for their input.

Need to pin python >= 3.6
Related issue: jupyter/jupyter_client#634

[beckermr]

This package seems prominent enough that a repodata patch would be better.

[davidbrochart]

But then we would have conda and PyPI out of sync, since we can't patch on PyPI?

[beckermr]

Ah you removed the pypi release?

[davidbrochart]

Not yet, but we have no choice but to yank the PyPI release.

[beckermr]

OK. yanking releases is a last resort but sometimes needed. LGTM.