Enforce signed header

[maidmaid]

Using signed headers, we can call more times certains POST endpoints. For example, POST /users/user-id/relationships endpoint without signing the limit is 20 calls per hour, with signature, we can do 60 (https://instagram.com/developer/limits/). To sign the header, here is the doc: https://instagram.com/developer/restrict-api-requests/#enforce-signed-header.

My implementation proposal:

• Add a boolean parameter enforce_signed_header, false by default.
• Add a ips parameter, 127.0.0.1 by default.
• If enforce_signed_header is true, we add a header Insta-X-Forwarded-For to request Guzzle having as value <ip_information>|<signature> as described in the documentation page.

[sesser]

Already in there. See https://github.com/sesser/Instaphp/blob/master/src/Instaphp/Instagram/Instagram.php#L140