Consider updating git submodule with dependabot

@alexdewar mentioned there is a way to keep the references to the git submodule up to date with dependabot. This could be useful for when this is in production.

Seems [pretty straightforward](https://stackoverflow.com/questions/74383554/is-there-any-way-to-update-a-certain-git-submodule-by-dependabot)

Start with the linked Stack Overflow guidance and inspect the repository's git submodule references. Determine how Dependabot should be configured to update that submodule, then verify that the configuration produces update proposals without affecting unrelated dependencies.

Written by the indexing model from the issue text.