Remove Docs requirement for roller

Remove the Docs requirement for changes authored by the roller service
account. Instead of the requirement being automatically met by those
changes, it doesn't even apply.

Change-Id: I893089d39e2a9e4d32111ead5aa02f3ca7afe059
Reviewed-on: https://pigweed-review.googlesource.com/c/Pigweed-Base/+/244118
Reviewed-by: Taylor Cramer <cramertj@google.com>