Symfony version(s) affected: 4.3.0

Description
Hi,

we have our redis server configured with requirepass option.
I get NOAUTH error when dispatching messages to Redis.

How to reproduce

So I read this docs page:
https://symfony.com/doc/current/messenger.html#redis-transport

It is not really documented how to specify connection password.

I started googling and found the docs page for redis cache: https://symfony.com/doc/current/components/cache/adapters/redis_adapter.html

They have the following DSN format for redis cache:

redis://[pass@][ip|host|socket[:port]][/db-index]
I thought redis message transport DSN format might be consistent with redis cache DSN format. So I tried the following:

MESSENGER_TRANSPORT_DSN="redis://redispass@redishost:6379"
That did not work.

I also tried passing options in config file:

framework:
    messenger:
        # Uncomment this (and the failed transport below) to send failed messages to this transport for later handling.
        # failure_transport: failed

        transports:
            # https://symfony.com/doc/current/messenger.html#transport-configuration
            async: 
                dsn: '%env(MESSENGER_TRANSPORT_DSN)%'
                options:
                    auth: redispass
                    password: redispass
            # failed: 'doctrine://default?queue_name=failed'
            # sync: 'sync://'

        routing:
            'App\Message\AsyncMessageInterface': async

That also did not work.

Similarly, I could not find a way to specify db-index.