Restrict dependabot checks to weekly instead of daily

[rak-phillip]

Summary

This sets dependabot to check for updates weekly instead of daily.

The current setting of daily appears to be quite aggressive and I think that a weekly check will allow us time to work through the backlog of updates. It also appears that the open-pull-requests-limit option¹ might apply to each individual directory as opposed to max items for a category. We might want to consider scaling this number down if we find that open PRs from dependabot are still too much.

Checklist

• The PR is linked to an issue and the linked issue has a Milestone, or no issue is needed
• The PR has a Milestone
• The PR template has been filled out
• The PR has been self reviewed
• The PR has a reviewer assigned
• The PR has automated tests or clear instructions for manual tests and the linked issue has appropriate QA labels, or tests are not needed
• The PR has reviewed with UX and tested in light and dark mode, or there are no UX changes

Footnotes

1. https://docs.github.com/en/code-security/dependabot/working-with-dependabot/dependabot-options-reference#open-pull-requests-limit- ↩