Run pyupgrade on src tree

[JHolba]

Approach
This PR is the result of running
pyupgrade --py311-plus src/**/*.py

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure unit tests pass locally after every commit (git rebase -i main --exec 'pytest tests/ert/unit_tests -n logical -m "not integration_test"')

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Create Backport PR to latest release

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 68.96552% with 9 lines in your changes missing coverage. Please review.

Project coverage is 91.94%. Comparing base (c9d43bc) to head (5918003).

Files with missing lines	Patch %	Lines
src/everest/bin/config_branch_script.py	60.00%	2 Missing ⚠️
src/everest/bin/everest_script.py	80.00%	1 Missing ⚠️
src/everest/config/everest_config.py	0.00%	1 Missing ⚠️
src/everest/detached/jobs/everserver.py	50.00%	1 Missing ⚠️
src/everest/jobs/__init__.py	0.00%	1 Missing ⚠️
src/everest/jobs/recovery_factor.py	0.00%	1 Missing ⚠️
src/everest/simulator/everest_to_ert.py	75.00%	1 Missing ⚠️
src/everest/util/__init__.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #9506   +/-   ##
=======================================
  Coverage   91.94%   91.94%           
=======================================
  Files         433      433           
  Lines       26748    26748           
=======================================
  Hits        24593    24593           
  Misses       2155     2155           

Flag	Coverage Δ
cli-tests	39.41% <75.00%> (ø)
everest-models-test	34.70% <24.13%> (ø)
gui-tests	72.15% <75.00%> (+<0.01%)	⬆️
integration-test	36.95% <37.93%> (-0.03%)	⬇️
performance-tests	51.98% <75.00%> (ø)
test	40.64% <65.51%> (+0.02%)	⬆️
unit-tests	74.14% <10.34%> (ø)

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