How to use Dependabot with private packages in GitLab
https://docs.github.com/en/code-security/dependabot/working-with-dependabot/configuring-access-to-private-registries-for-dependabot
https://docs.github.com/en/code-security/dependabot/working-with-dependabot/configuring-access-to-private-registries-for-dependabot