Update dependabot interval to weekly once backlog is cleared

[ColePBryan]

Dependabot interval is set to daily right now to try to get through backlog. Once that changes we should update it to weekly interval to reduce PR noise.

See:

• https://docs.github.com/en/enterprise-cloud@latest/code-security/dependabot/dependabot-version-updates/configuring-dependabot-version-updates#example-dependabotyml-file

In the example above, if the Docker dependencies were very outdated, you might want to start with a daily schedule until the dependencies are up-to-date, and then drop back to a weekly schedule.

Docs for making the change:

• https://docs.github.com/en/enterprise-cloud@latest/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#scheduleinterval