Documentation: stable-kernel-rules: fix broken git urls

git.kernel.org links don't work (fatal: repository ... not found).
Update them with the current style from https://git.kernel.org



There is no HTTP option, so also switch HTTP -> HTTPS.

Signed-off-by: Andrii Bordunov <andrew.bordunov@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>