Minor: Add youtube to the group list (#1816)
Minor: Add youtube to the group list (#1816)

I know that it says that we do not list them all but it is easier if we
actually list the ones we know about.

Signed-off-by: Julien Pivotto <df1ed88a312a603dfee9f157a90fa8f7f195ab59@inuits.eu>
prometheus/docs,prometheus/docs,prometheus/docs