Disable pr-tools.yml due to security vulnerability

[jminor]

It has been brought to our attention that use of pull_request_target creates an opportunity for bad actors to do damage by posting pull requests that run undesirable code within this project's base repo. This PR disables the one workflow that uses that feature.

I opted to leave that code in place, just commented out, in the hopes that some alternate safer implementation becomes available.

Read more here:

• https://www.stepsecurity.io/blog/hackerbot-claw-github-actions-exploitation
• https://paulserban.eu/blog/post/why-is-pullrequesttarget-so-dangerous-a-security-explainer/

[jminor]

FYI, we have some limited protection from this attack due to this setting on the repo which requires a maintainer to approve actions from new contributors, but a misleading PR could trick someone into allowing it to run.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.15%. Comparing base (f3cb304) to head (d772c15).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1996   +/-   ##
=======================================
  Coverage   85.15%   85.15%           
=======================================
  Files         181      181           
  Lines       12783    12783           
  Branches     1206     1206           
=======================================
  Hits        10885    10885           
  Misses       1715     1715           
  Partials      183      183           

Flag	Coverage Δ
py-unittests	85.15% <ø> (ø)

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[darbyjohnston]

LGTM