it should apply header filter for response as well

[sajjadakhter]

i wanted to exclude headers like set-cookie from logs but looks like it only processes request headers.

[tellnes]

It could probably be done using the additionalRequestFinishData callback and specifying the res property. But that is a hack and this sounds like a reasonable feature to have. So I'm open to pr.

I'm not sure if we should just change the existing feature to include filtering on the response headers or add some new configuration options for it.