Yielding output is not verified

[JeremyPansier]

• A transaction holding an yielding output must be signed by the incomed output recipient.
• A yielding utxo must be updated when the recipient is not registered anymore.

	for address := range blockchain.registeredAddresses {
		isPohValid, err := blockchain.registry.IsRegistered(address)
		if err != nil {
			return fmt.Errorf("failed to get proof of humanity: %w", err)
		}
		if isPohValid {
			addedRegisteredAddresses = append(addedRegisteredAddresses, address)
		} else {
			removedRegisteredAddresses = append(removedRegisteredAddresses, address)
			for _, utxo := range blockchain.utxosByAddress[address] {
				if utxo.IsYielding() {
					//utxo.ChangeExpiration
				}
			}
		}
	}