Add Python 3.13 to Testing Infrastructure

[mrmundt]

Fixes NA

Summary/Motivation:

We want to be as updated as possible with our Python versions.

NOTE: We will be removing Python 3.8 support after the next release.

Changes proposed in this PR:

• Adds Python 3.13

Legal Acknowledgement

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1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[jsiirola]

Looks good, although we might hold off merging for a little just to keep the load on GHA down while we prep for the release?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.67%. Comparing base (364e7f1) to head (f35b608).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3401   +/-   ##
=======================================
  Coverage   88.66%   88.67%           
=======================================
  Files         879      879           
  Lines      100374   100379    +5     
=======================================
+ Hits        88999    89007    +8     
+ Misses      11375    11372    -3     

Flag	Coverage Δ
linux	86.12% <100.00%> (+<0.01%)	⬆️
osx	76.11% <100.00%> (+<0.01%)	⬆️
other	86.62% <100.00%> (+<0.01%)	⬆️
win	84.50% <100.00%> (+0.03%)	⬆️

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