notification of added dependencies before upgrade

[bartart3d]

Is your feature request related to a problem? Please describe.
After latest upgrade (to 6.24) from the admin window, calibre-web failed to start because the newer version depended on a python library which was not needed in the previous release. This dependency now was netifaces-plus.

Describe the solution you'd like
It would be nice to be notified of the change in dependencies from the admin window within calibre-web to avoid such issue's. A simple warning, maybe with a short description, or a link to the github wiki with the necessary explanation on how to install these new dependencies would be good.