[BUG] Async client is missing ssl_assert_hostname implementation

[merlinz01]

What is the bug?

The ssl_assert_hostname parameter has no effect on the AsyncOpenSearch client.

How can one reproduce the bug?

client = AsyncOpenSearch(hosts='my.opensearch.with.selfsigned.certs', ssl_assert_hostname=False)
await client.search(...)

opensearchpy.exceptions.ConnectionError: ConnectionError(Cannot connect to host my.opensearch.instance:9200 ssl:True [SSLCertVerificationError: (1, "[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: Hostname mismatch, certificate is not valid for 'my.opensearch.instance'. (_ssl.c:1000)")]) caused by: ClientConnectorCertificateError(Cannot connect to host my.opensearch.instance:9200 ssl:True [SSLCertVerificationError: (1, "[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: Hostname mismatch, certificate is not valid for 'my.opensearch.instance'. (_ssl.c:1000)")])

What is the expected behavior?

The connection should succeed even if the hostname does not match.

What is your host/environment?

N/A

Do you have any screenshots?

N/A

Do you have any additional context?

The parameter is documented in the function docs:

opensearch-py/opensearchpy/_async/http_aiohttp.py

Line 120 in 6fa54a7

:arg ssl_assert_hostname: use hostname verification if not `False`

I believe the parameter works with the urllib3-based client.

I'm working on a PR to fix this.