treat basic auth and bearer auth the same

[grosser]

... and avoid sending in the headers twice

found during #532 so preferable merge here first and then rebase for a smaller diff

@cben

[cben]

Nice! But this is printing warnings. Actually basic_auth also does now.

WARNING: Faraday::Connection#authorization is deprecated; it will be removed in version 2.0.
While initializing your connection, use #request(:authorization, ...) instead.
See https://lostisland.github.io/faraday/middleware/authentication for more usage info.
WARNING: Faraday::Connection#basic_auth is deprecated; it will be removed in version 2.0.
While initializing your connection, use #request(:basic_auth, ...) instead.
See https://lostisland.github.io/faraday/middleware/authentication for more usage info.

(deprecation was here: lostisland/faraday#1306)

I think it's supposed to be (untested):

Suggested change

	connection.basic_auth(@auth_options[:username], @auth_options[:password])
	elsif @auth_options[:bearer_token]
	connection.authorization(:Bearer, @auth_options[:bearer_token])
	connection.request(:basic_auth, @auth_options[:username], @auth_options[:password])
	elsif @auth_options[:bearer_token]
	connection.request(:authorization, 'Bearer', @auth_options[:bearer_token])

[cben]

I like the overall simplification, but doesn't converting to file name -> file content go contrary to goals of #530?
Well, no @auth_options[:bearer_token_file] will still exist.

LGTM. close-cycling to re-run failed ruby 2.5 (looks like unrelated flake)

The faraday warnings thing is actually orthogonal, I could merge this as-is then send an MR.

[grosser]

plz merge and let's fix warnings in it's own PR :)

[grosser]

I can also tack on the warning change if you want