Description
automatically assign reviewers to dependabot tickets for better visibility

Review Instructions
n/a

Issue
https://ucsc-cgl.atlassian.net/browse/SEAB-5002
https://github.blog/changelog/2020-07-15-assign-a-github-team-to-review-dependabot-pull-requests/

Please make sure that you've checked the following before submitting your pull request. Thanks!

• Check that you pass the basic style checks and unit tests by running ./mvnw clean install
• If this PR is for a user-facing feature, create and link a documentation ticket for this feature (usually in the same milestone as the linked issue). Style points if you create a documentation PR directly and link that instead.