Add Renovate and Pin Dependencies for Stable CI and Automated Updates

[harryswift01]

Summary

This PR introduces Renovate to automatically manage and update pinned dependencies. It adds the necessary Renovate configuration, workflow, and dependency pinning to ensure predictable CI behavior and safe, controlled dependency upgrades.

Changes

Add Renovate configuration

• Added .github/renovate.json with extends: ["config:base"] and rangeStrategy: "bump".
• Ensures Renovate can update pinned versions via pull requests.

Add Renovate GitHub Actions workflow

• Added .github/workflows/renovate.yaml to run Renovate daily at 8 AM UTC.
• Configured Renovate to authenticate using the RENOVATE_TOKEN secret.
• Allows automated dependency checks and updates.

Pin dependencies in pyproject.toml

• Replaced unpinned (>=) versions with strict pinned (==) versions.
• Updated optional testing and pre-commit dependencies to pinned versions.
• Ensures deterministic CI runs and consistent dependency resolution.

Impact

• CI becomes predictable and unaffected by upstream dependency changes.
• Renovate will automatically propose version updates through PRs.
• Reduced risk of merging incompatible or unstable dependency combinations.
• Makes debugging CI failures easier, as dependency versions are well-defined.

[jimboid]

Looks good. Will just have to monitor it for a while to make sure it is working as we want