Update Renovate to include PEP 621 support and replace-based dependency ranges

[harryswift01]

Summary

This PR updates the Renovate configuration to improve how dependency ranges are managed for the pyproject.toml file. Renovate will now maintain only the range of dependencies that are confirmed working via CI, and optional PEP 621 extras (testing, docs, pre-commit) are now included for automated updates.

Changes

Enable PEP 621 manager:

• Added "enabledManagers": ["pep621"] so Renovate can update dependencies in pyproject.toml.
• Ensures that all main project dependencies are detected and managed correctly.

Add Renovate range strategy replace:

• Configured "rangeStrategy": "replace" to ensure dependency ranges are upgraded only when the new versions are verified to work.
• Prevents overly broad ranges while ensuring outdated/incompatible versions are removed once CI passes.

Manage optional dependencies (testing, docs, pre-commit):

• Added "pep621": { "enabled": true } to ensure Renovate also updates:
  • [project.optional-dependencies].testing
  • [project.optional-dependencies].docs
  • [project.optional-dependencies].pre-commit
• Keeps all extras up to date alongside main dependencies.

Impact

• Ensures dependency ranges stay minimal, correct, and test-verified.
• Removes outdated dependency versions only when the new versions are confirmed working.
• Keeps all optional extras (docs/test/dev tools) automatically updated.
• Improves long-term maintainability of the project’s dependency ecosystem.