Remove link rel references to AMP version

[jrdi]

Link rel tag for amphtml should be removed to have a valid AMP version

[t-jindai]

@jrdi Thank you for you PR and sorry for late reply...

Could you pass me AMP official document link which mention that Link rel tag for amphtml should be removed to have a valid AMP version.

Here is my understanding..

AMP First

needs rel[amphtml]

https://amp.dev/documentation/guides-and-tutorials/start/create/prepare_for_discovery/?format=websites

Paired AMP :

not mentioned about whether amp page could have rel[amphtml] or not.

But AMP validator would not detect as invalid if the page has rel[amphtml].