Weekly is more frequent than necessary.

The plugin archetype recommends monthly.

What has been done

1. Reduce update check from weekly to monthly so that maintainers only see new dependencies once a month

How to test

1. Merge to the master branch
2. Confirm that the check runs only once a month

Checklist

• Git commits follow best practices
• Build passes in Jenkins
• Appropriate tests or explanation to why this change has no tests
• Pull Request is marked with appropriate label (see .github/release-drafter.yml)
• For dependency updates: links to external changelogs and, if possible, full diffs