FR: Expand deprecation warning to include reason or source

[hpl002]

This might be very helm specific, but still.

Had a very old helm revision that triggered a deprecation warning. Would be nice if it simply told me the source of this warning as opposed to me having to dig through

Helm encodes the revision directly in the secret name so it should be fairly accessible :D

[stepanstipl]

Thanks for the idea 👍 - I was previously against adding too much info in the default output to keep it simple, but at the same time, it might be worth making this more configurable, i.e. custom/extended output format, related to #405.