security_protocol argument docstring does not mention SASL_SSL or SASL_PLAINTEXT

[gabrielmbmb]

Describe the bug

The security_protocol argument docstring in aiokafka.{AIOKafkaConsumer, AIOKafkaProducer} does not mention SASL_SSL and SASL_PLAINTEXT as possible values but they are as mentioned in the sasl_mechanism argument docstring.

aiokafka/aiokafka/producer/producer.py

Lines 140 to 142 in 57439a6

	security_protocol (str): Protocol used to communicate with brokers.
	Valid values are: ``PLAINTEXT``, ``SSL``. Default: ``PLAINTEXT``.
	Default: ``PLAINTEXT``.

aiokafka/aiokafka/consumer/consumer.py

Lines 170 to 171 in 57439a6

	security_protocol (str): Protocol used to communicate with brokers.
	Valid values are: ``PLAINTEXT``, ``SSL``. Default: ``PLAINTEXT``.

aiokafka.client.AIOKafkaClient does mention all the possible values:

aiokafka/aiokafka/client.py

Lines 77 to 79 in 57439a6

	security_protocol (str): Protocol used to communicate with brokers.
	Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL.
	Default: PLAINTEXT.

Expected behaviour
security_protocol argument docstring mentions SASL_SSL and SASL_PLAINTEXT as possible values.

Environment (please complete the following information):

• aiokafka version (python -c "import aiokafka; print(aiokafka.__version__)"): 0.8.0
• kafka-python version (python -c "import kafka; print(kafka.__version__)"):
• Kafka Broker version (kafka-topics.sh --version):
• Other information (Confluent Cloud version, etc.):