Add renovate github action

[raynhamdev]

Background

As part of Sensible Default work, we'd like to add renovate to enable automatically dependency update in this repository.

Both Renovate and Dependabot are working well with GitHub. We chose Renovate because it is easier to configure for grouped PR than Dependabot. Additionally, Renovate has been used in many Octopus repositories (including Server) and has proved it is integrated well with OctoBob to approve/merge dependency update PRs automatically.

This PR adds Renovate GitHub action to the repo.

• Run at 8AM, Mon-Fri
• Auto-merge is not yet enabled.
• Auto-approval by OctoBob is enabled.

[sc-65919]

How to review this PR

Quality :heavy_check_mark:

[shortcut-integration[bot]]

This pull request has been linked to Shortcut Story #65919: Implement dependency auto-updating for Halibut repository.