feat: switch to renovate (#4131)
<!-- CURSOR_SUMMARY -->
> [!NOTE]
> Migrates automated dependency updates from Dependabot to Renovate.
>
> - Removes `.github/dependabot.yml`
> - Adds `renovate.json5` extending
`github>unstructured-io/renovate-config` to manage updates via Renovate
>
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
2a2b7281b1590e731f10b24fa6bec2fb5448f4ac. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->
