fix(rabbitmq): using __routeArguments__ key to allow pipe injection

[sezanzeb]

Fixes #645

nestjs regular @Param decorator and such adds the pipes to the metadata (via the reflection methods) using the '__routeArguments__' key (https://github.com/nestjs/nest/blob/93b99d09ed84640815fc3aa99196cf94e692bc4d/packages/common/decorators/http/route-params.decorator.ts#L80)

The DependenciesScanner of nestjs then loads the '__routeArguments__' and injects the pipes in reflectParamInjectables (https://github.com/nestjs/nest/blob/master/packages/core/scanner.ts)

golevelup/nestjs however uses the 'RABBIT_ARGS_METADATA' key for it (https://github.com/golevelup/nestjs/blob/c927cb12f5203fe4739027fc54d78c6ae2629cfb/packages/rabbitmq/src/rabbitmq.decorators.ts), so the scanner will never load and inject them.

I just changed it to '__routeArguments__', and then pipes were correctly created, and their dependencies injected. I don't know enough about the internals to judge if this causes other side-effects. Hopefully tests will catch it all. I wasn't able to run tests locally, so I'm waiting for the ci pipeline to run.

[underfisk]

Thank you for pushing this PR.
I did think about this before and I believe it was intentional not to have the same key so as not to confuse with controllers. Unfortunately I've been wanting to refactor the package as RabbitMQ providers should have been controllers in the first place but if you're change doesn't introduce any breaking change, I'll be happy to merge

[sezanzeb]

At least I haven't observed any problems with this until now. I'll try working with this a bit more over the next one or two weeks, and report back if there have been any unexpected bugs.