Provider key is not respected #17

According to the documentation I should be able to pass in a provider key like with serverless.yml, SCF ignores the one in the other file and compalins that the provider key does not exist

I am using 4.17.1, documentation says this key should exist https://www.serverless.com/containers/docs/deployment#essential-configuration

It would be great if a specification could be published to the docs rather than me guessing