Reminder: action required when updating dependencies or build options

[Michael Catanzaro <mcatanzaro gnome org>]

Hi developers,

Please remember that action is required when updating your dependencies 
or build options. You need to either make sure gnome-build-meta is OK 
with your changes, or ask release team to investigate on your behalf.

We've had at least four separate breakages from four separate projects 
in the past few days. This is too much. Please be careful. Thanks!

Michael