Fixing xml configuration for routing-keys

[mateuszsip]

This is a follow-up to #210.

Currently setting multiple routing keys using xml configuration:

<queue-options>
    <name>test-queue</name>
    <routing-keys>
        <routing-key>foo</routing-key>
        <routing-key>bar</routing-key>
    </routing-keys>
</queue-options>

Ends with:

[Symfony\Component\Config\Definition\Exception\InvalidTypeException]                                                                                   
  Invalid type for path "old_sound_rabbit_mq.consumers.test_consumer.queue_options.routing_keys.routing_key". Expected scalar, but got array. 

But works for single routing key, that is confusing:

<queue-options>
    <name>test-queue</name>
    <routing-keys>
        <routing-key>foo</routing-key>
    </routing-keys>
</queue-options>

There is a solution mentioned in #197

<queue-options>
    <name>test-queue</name>
    <routing-keys>
        foo
    </routing-keys>
    <routing-keys>
        bar
    </routing-keys>
</queue-options>

But it would be nice to use the same valid way that #210 introduced for routing keys.

After merge, configuration like this:

<queue-options>
    <name>test-queue</name>
    <routing-key>foo</routing-key>
    <routing-key>bar</routing-key>
</queue-options>

Is valid and works as expected.

[stloyd]

Thanks @kejwmen !

[aosmialowski]

@stloyd can we have a tag, please? For our team, fixing this issue is quite crucial.