Sensitive headers logged in info log

[yii-bot]

This issue has originally been reported by @sanjakovac at yiisoft/yii2#16488.
Moved here by @samdark.

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What steps will reproduce the problem?

• Turn on info log in your application
• Use function Yii/authclient/BaseOAuth.SendRequest to do Http POST request

What is the expected result?

Yii/httpclient/StreamTransport.send should log only basic information about request.
Token should not be logged in info log, since it may contain sensitive information. Values of headers carrying sensitive information, should be obfuscated.

What do you get instead?

Yii/httpclient/StreamTransport.send will log all the headers including username/password if it was sent with request.

Additional info

Q	A
Yii httpclient version	2.0.6.0
PHP version	7.0
Operating system	MacOS