Comment 2 for bug 1918879

- the name of api is 'Update an encryption type', the name of function is update in '/cinder/api/contrib/volume_type_encryption'

- follow is a request exemple:
/v3/{project_id}/types/{volume_type_id}/encryption/{encryption_id}

{
    "encryption":{
        "key_size": 64,
        "provider": "luks",
        "control_location":"back-end",
        "cipher": "aes-xts-plain64"
    }
}

- the relese is W