chore: Update GitHub Actions to latest versions

[TheRealAgentK]

Description 📝

Purpose:

Update GitHub Actions to their latest major versions for security and compatibility improvements.

Approach:

Bump action versions in python-checks.yml:

• actions/checkout@v3 → v4
• actions/setup-python@v4 → v5

Type of change

• ci: CI configuration change

Updates

• Updated actions/checkout from v3 to v4
• Updated actions/setup-python from v4 to v5

Related issues

Closes #129

Test plan 🧪

CI will run on this PR to validate the updated actions work correctly across all Python versions (3.9-3.14).

Author to check 👓

• Project and all contained modules builds successfully
• Self-/dev-tested
• Unit/UI/Automation/Integration tests provided where applicable
• Code is written to standards
• Appropriate documentation written (code comments, internal docs)

Reviewer to check ✔️

• Project and all contained modules builds successfully
• Change has been dev-/reviewer-tested, where possible
• Unit/UI/Automation/Integration tests provided where applicable
• Code is written to standards
• Appropriate documentation written (code comments, internal docs)

[Copilot]

Pull request overview

This PR updates GitHub Actions to their latest major versions in the CI workflow to ensure security and compatibility improvements.

Changes:

• Updated actions/checkout from v3 to v4
• Updated actions/setup-python from v4 to v5

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