Update bundled jQuery to 3.6.4.

[bdice]

Description

This PR resolves a security warning about jQuery versions less than 3.5.0. See here for details: https://blog.jquery.com/2020/04/10/jquery-3-5-0-released/

Checklist:

• [x] I am familiar with the Contributing Guidelines.
• [x] I agree with the terms of the Contributor Agreement.
• [x] The changes introduced by this pull request are covered by existing or newly introduced tests.
• [x] The package documentation and framework documentation in signac-docs are up to date with these changes.
• [x] I have updated the changelog and added any related issue and pull request numbers for future reference.

[codecov[bot]]

Codecov Report

Merging #184 (4c4be76) into main (abffb4e) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #184   +/-   ##
=======================================
  Coverage   68.50%   68.50%           
=======================================
  Files          20       20           
  Lines         816      816           
  Branches      150      150           
=======================================
  Hits          559      559           
  Misses        218      218           
  Partials       39       39           

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