Remove add-reviewed-by-action Github Action

This Github Action has never worked and it has already been achieved
with the reason "Unfortunately, this action has a critical issue with
forked repositories, and should no longer be used" [1].

So remove it to also avoid noise from "Run failed: Add Reviewed-by"
emails.

[1] https://github.com/ntessore/add-reviewed-by-action/

Signed-off-by: Coiby Xu <[email protected]>

Author: coiby