Send more info with update resource notification

[PrasadG193]

Is your feature request related to a problem? Please describe.
BotKube, when configured to send update events on resources, sends only Resource updated message with the notification which doesn't make much sense. Instead, it should also provide information about what has changed with that update

Describe the solution you'd like
BotKube should provide resource spec diff or about the fields that are updated with resource update notification