disable_odoo_online: make it clear in README, that feature works in odoo community only

[hbrunn]

@pedrobaeza this is exactly not the case. There's code making the override only effctive if the version number doesn't look like enterprise: https://github.com/yelizariev/server-brand/blob/04607c9195451845d996d188dee446ae2afdf223/disable_odoo_online/models/publisher_warranty_contract.py#L13 If you want to be picky, we can say that a breach of contract has nothing to do with legality in the sense of crimes, but well, I don't think we need to argue this point here

[pedrobaeza]

Ah, OK, I didn't remember that.