Dependabot YML invalid

[KochTobi]

Describe the bug

The current version of the dependabot.yml is not valid according to https://dependabot.com/docs/config-file/validator/

To Reproduce

Steps to reproduce the behavior:

1. Validate yml
2. observe invalidity

Expected behavior
The dependabot.yml is valid.

Additional context
The valid options:
https://docs.github.com/en/code-security/supply-chain-security/keeping-your-dependencies-updated-automatically/configuration-options-for-dependency-updates