Upgrade guide to v0.9.x doesn't mention `krillc pubserver server init`

[Ximon Eighteen]

Krill v0.9.0 introduced the krillc pubserver server init command as documented at https://krill.docs.nlnetlabs.nl/en/0.9.0/publication-server.html where it also says:

You need to initialise your Publication Server using the base URIs as exposed by your Repository Servers.

However https://krill.docs.nlnetlabs.nl/en/stable/upgrade.html doesn't mention that this step is now required whereas in earlier versions it was not.

Thanks to @aistiszen for bringing this to our attention 👏 !