Update action link in readme file

[jandrus-lviv]

Hi!

It would be great to update the action link in the readme file, because the actual link does not work correctly.

I suggest changing that link for this one: https://www.w3schools.com/action_page.php

With this changing will be more convenient to test sending data from solutions of this task.

[mukutiuk]

https://mukutiuk.github.io/layout_html-form/
https://mukutiuk.github.io/layout_html-form/report/html_report/