ci: modernize CI pipeline and add example validation

[AswaniSahoo]

What this PR does

Modernizes the CI pipeline and adds a new example validation job to catch configuration and syntax errors in examples before they are merged.

Changes

CI Pipeline Updates (.github/workflows/main.yaml):

• Update Python test matrix from [3.7, 3.8, 3.9] to [3.9, 3.10, 3.11, 3.12]
  • 3.7, 3.8 are EOL (June 2023, October 2024 respectively)
  • 3.9 is retained as minimum for backward compatibility (EOL October 2025)
  • 3.10-3.12 are currently supported by the Python Software Foundation
• Update actions/checkout from v3 to v4 and actions/setup-python from v3 to v5 (v3 uses deprecated Node.js 16 runtime)
• Replace hardcoded pip==24.0 with pip install --upgrade pip
• Apply --max-positional-arguments=10 universally for pylint (no longer needs Python version conditional since all matrix entries now install pylint >= 3.3.0, see Pylint Errors Due to Compatibility Issues with Pylint3.9 #157)
• Add new example-validation job that:
  • Validates all 37 benchmarkingjob.yaml files are parseable
  • Checks all 542 example Python files for syntax errors
  • Verifies core ianvs package can be imported after installation

Minimum Python Version (setup.py):

• Update python_requires from ">=3.6" to ">=3.9"
• Update version assertion to match

YAML Bug Fix (examples/cifar100/fci_ssl/fedavg/benchmarkingjob.yaml):

• Fix syntax error on line 17: algorithms:conda → algorithms: (accidental concatenation, discovered during local validation testing)

Local Verification

Ran validation locally before submitting:

YAML:   37/37 files passed (after fixing the pre-existing error)
Python: 542/542 files passed - no syntax errors

Relationship to #230

This addresses the CI pipeline component of the Comprehensive Example Restoration initiative:

"Build a CI pipeline testing examples with GitHub Actions against multiple Python versions, critical Ianvs/upstream updates, and block PRs that break validated examples"

Fixes #411

[kubeedge-bot]

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[kubeedge-bot]

Welcome @AswaniSahoo! It looks like this is your first PR to kubeedge/ianvs 🎉

[gemini-code-assist]

Code Review

This pull request updates the minimum Python version requirement to 3.9 in setup.py and corrects a syntax error in the benchmarkingjob.yaml configuration. Feedback was provided to replace the assert statement for the Python version check with an explicit if condition and sys.exit() to ensure the check is not bypassed when running Python with optimization flags.