Import Debian changes 18.1-5

python-pip (18.1-5) unstable; urgency=medium

  * Team upload.
  * Refresh hands-off-system-packages.patch.
  * Add Properly_catch_requests_HTTPError_in_index.py.patch: this fixes 404
    when using --extra-index-url due to the way we de-bundle python-requests
    from pip. Thanks to Fabio Natali <me@fabionatali.com> for the bug report,
    Clark Boylan for the patch, and all of the OpenStack infra team for their
    help and involving me for this fix (Closes: #837764).
3 jobs for debian/bullseye