Refactor/modernize type hints

[jlnav]

Addresses #1378

[codecov]

Codecov Report

Attention: Patch coverage is 97.41935% with 4 lines in your changes missing coverage. Please review.

Project coverage is 76.48%. Comparing base (18db310) to head (26a8ddd).
Report is 149 commits behind head on develop.

Files with missing lines	Patch %	Lines
libensemble/executors/balsam_executor.py	0.00%	4 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (18db310) and HEAD (26a8ddd). Click for more details.

HEAD has 5 uploads less than BASE

Flag	BASE (18db310)	HEAD (26a8ddd)
	15	10

Additional details and impacted files

@@             Coverage Diff              @@
##           develop    #1381       +/-   ##
============================================
- Coverage    92.71%   76.48%   -16.23%     
============================================
  Files           88       88               
  Lines         8017     8008        -9     
  Branches      1435     1428        -7     
============================================
- Hits          7433     6125     -1308     
- Misses         384     1667     +1283     
- Partials       200      216       +16     

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[jlnav]

These changes appear to be from Python 3.10 onward