MAINT: Upgrade to actions/setup-python@v5

[rrjbca]

Description

Upgrade actions/setup-python to version 5 (v4 uses deprecated version of Node.js)

Checklist

• [x] Follow the Contributor Guidelines
• [ ] Write unit tests
• [ ] Write documentation strings
• [ ] Assign someone from your working team to review this pull request
• [x] Assign someone from the infrastructure team to review this pull request