Chore: Adjust Python Version

[Fovty]

Motivation

Since we bumped the minimum required Python version to 3.9 in pyproject.toml, we should align our Python test workflow to use the same version.

Changes

• Updated the Python version in the GitHub Actions workflow for tests from 3.8 to 3.9.

Tests Done

• Verified that the GitHub Actions workflow runs successfully with the updated Python version.

TODO

• Assign myself to this PR.

[github-actions]

File	Coverage
All files	97%	✅
test_autoscale_resource.py	99%	✅
test_cmd.py	100%	✅
test_events.py	100%	✅
test_grace_period.py	100%	✅
test_ignore_if_labels_dont_match.py	100%	✅
test_main.py	100%	✅
test_pods_force_uptime.py	100%	✅
test_resources.py	100%	✅
test_scaler.py	95%	✅
test_time.py	100%	✅

Minimum allowed coverage is 70%

Generated by 🐒 cobertura-action against d0740b8

[samuel-esp]

LGTM