Add ssl_ca_path support to async Redis client

[majiayu000]

Summary

Fixes #3414

Add ssl_ca_path parameter to the async Redis client and SSLConnection to enable specifying a directory of CA certificates, matching the sync client's functionality.

Changes

• Add ssl_ca_path parameter to Redis.__init__
• Add ssl_ca_path parameter to SSLConnection.__init__
• Add ca_path parameter to RedisSSLContext
• Pass capath to ssl.SSLContext.load_verify_locations()

Usage

from redis.asyncio import Redis

client = Redis(
    host="localhost",
    ssl=True,
    ssl_ca_path="/path/to/ca/certs/directory",
)

🤖 Generated with Claude Code

[petyaslavova]

Hi @majiayu000, thank you for your contribution!
Can you please add some tests to the change to cover the new input?
I also noticed that for the sync cluster client, it needs to be added to the REDIS_ALLOWED_KEYS tuple - would you please add it there as well?

[majiayu000]

Thanks for the review! I've addressed the feedback:

1. Added test_ssl_ca_path_parameter test in tests/test_asyncio/test_ssl.py to verify the parameter is properly passed through to SSLConnection
2. Added ssl_ca_path to REDIS_ALLOWED_KEYS tuple in redis/cluster.py for sync cluster client support

Please take another look when you have a chance.