docs(aws-lambda) add request forwarding options
docs(aws-lambda) add request forwarding options

Options added in Mashape/kong#2823

Signed-off-by: Thibault Charbonnier <3c2e9133e272cb489e2fea0c4328cf56b08e4226@me.com>

Mashape/getkong.org,Mashape/getkong.org,Mashape/getkong.org