add dependabot config - Githubissues

Why / What

This PR adds dependabot config

After approving the PR, the reviewer should check the boxes below. See the Reviewer Checklist company standard for more info on these bullet points.

[ ] Do you understand the reasoning behind the need for the changes?
[ ] Given only new or existing tests*, do you feel confident that all changes work as intended and solve the problem at hand?
[ ] Are all success and failure paths accounted for in the tests? If not, are the omissions explained/justified?
[ ] If coverage ignores are present, is justification provided inline (or linked to) or is a link to a ticket to address in the future provided?
[ ] Are you willing to accept the same responsibility for this code as the author?

*If existing tests, requester should point out what applies

Measure with bin/test_cov or some other means. You can find html coverage levels in coverage/index.html or in stdout.

After a successful test run, you can also see calculated and merged coverage, per branch, on Grafana