Documentation "latest" should be triggered daily?

[ROunofF]

What would you like to be added: To ensure people can view the latest state of the documentation, docs should be release in a timely matter for latest. I propose to add a schedule event triggering daily to the docs workflow and adjust https://github.com/kubernetes-sigs/external-dns/blob/master/.github/workflows/docs.yaml#L42

Why is this needed: Latest documentation seen many changes, but haven't been updated on the website since Nov 14th as it currently needs to be triggered manually.

@mloiseleur WDYT? Small improvement following #6092 as an example