Add dependabot configuration

[yeikel]

Problem

Keeping the dependencies up to date is crucial to ensure that the project stays secure and updated.

Solution

See https://github.blog/2020-06-01-keep-all-your-packages-up-to-date-with-dependabot/

Does this solution apply anywhere else?

• [x] yes
• [ ] no

If yes, where?

Any repository with dependencies should aim to keep the dependencies up to date automatically

[cla-assistant[bot]]

All committers have signed the CLA.