Migrate from the legacy dependabot configuration to the new dependabot config format

[luzfcb]

Description

Related documentation:

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

https://docs.github.com/en/github/administering-a-repository/enabling-and-disabling-version-updates

https://docs.github.com/en/github/visualizing-repository-data-with-graphs/about-the-dependency-graph#supported-package-ecosystems

https://docs.github.com/en/github/administering-a-repository/customizing-dependency-updates

Rationale

We need to keep tracking the dependencies update