Fix Renovate package rules not matching and request review on PRs

[harryswift01]

Summary

This PR fixes the Renovate configuration so that dependency updates follow the intended widen strategy, and so that review is requested from maintainers instead of assigning them.

Changes

Fix package rules matching:

• Change matchManagers on both pyproject.toml package rules from ["pep621"] to ["poetry", "pep621"]. Renovate processes our pyproject.toml with the poetry manager, so the previous rules never matched.
• Keep pep621 in the list so the rules still apply if the file is routed back to that manager.

Request review instead of assigning:

• Replace assignees with reviewers for harryswift01 and jimboid, so Renovate PRs request their review.

Impact

• Production dependency updates now use widen, so only the upper bound of each version range moves and lower bounds (floors) are preserved.
• Renovate PRs request review from the maintainers, so they no longer assign the PR.
• Existing open Renovate PRs keep their old ranges until they are rebased from the Dependency Dashboard.

[jimboid]

Looks like it should work. Lets merge and see