docs: Fix download method of probability models archive in pull plot notebook

[matthewfeickert]

Description

The nightly notebook tests are failing due to the pullplot notebook because of changes in HEPData. Adopting the new DOIs for the probability models and using pyhf contrib download to properly deal with HEPData headers fixes this.

This is a similar PR to PR #1721.

Checklist Before Requesting Reviewer

• Tests are passing
• "WIP" removed from the title of the pull request
• Selected an Assignee for the PR to be responsible for the log summary

Before Merging

For the PR Assignees:

• Summarize commit messages into a comprehensive review of the PR

* Use stable DOI https://doi.org/10.17182/hepdata.89408.v3/r2 to download
probability models archive from HEPData.
* Use `pyhf contrib download` as it can properly accept HEPData headers.
* Change directories for the impact plot notebook test so that the paths used
in the notebook do not have to be changed to accommodate testing paths.
* This PR is complimentary to PR #1721

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[matthewfeickert]

If GHA workflow https://github.com/scikit-hep/pyhf/actions/runs/1548373034 passes then this is good to go. 👍

[codecov]

Codecov Report

Merging #1724 (2a098bc) into master (e3c21aa) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1724   +/-   ##
=======================================
  Coverage   98.12%   98.12%           
=======================================
  Files          64       64           
  Lines        4269     4269           
  Branches      682      682           
=======================================
  Hits         4189     4189           
  Misses         46       46           
  Partials       34       34           

Flag	Coverage Δ
contrib	26.25% <ø> (ø)
doctest	60.59% <ø> (ø)
unittests	96.18% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/pyhf/cli/complete.py	100.00% <ø> (ø)
src/pyhf/contrib/utils.py	100.00% <ø> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 29bc6da...2a098bc. Read the comment docs.