Invalid External credentials example in docs

[aiexz]

I was trying to connect to SSL rabbitmq server with external server and failed with the example in the docs.

There was an issue(#479) related to this problem and code from there works just fine.

Adding auth='external' argument to connect_robust seems to solve the problem https://gist.github.com/aiexz/7f93fd6b91fe10d280dee6d6395bdbd4

[RomanKhudobei]

Omg, thank you. I've been searching this simple thing for couple of hours. It really should be stated in documentation

[mosquito]

@RomanKhudobei don't you want add some example in documentation? Or add it here, I will add it.