chore(dependabot): Group together policy reasoner updates

[DanielVoogsgerd]

This should in theory group together all the policy reasoner updates, as they should be updated in tandem.

I don't really have a way to check if this is going to work, nor do I have the access to see if it did afterwards.

@Lut99, Could you check if this makes sense?

The documentation on this particular setting can be found here:
https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#example-1

After merging, you can see in the same panel where you enabled it if the file is properly parsed.

[Lut99]

Do you want to re-base w.r.t. #163 first?