Update signl4/README.md
Update signl4/README.md

Co-authored-by: Ursula Chen <147c9617a78ab10ffd7ce1432726aec7b517bfbf@users.noreply.github.com>
DataDog/integrations-extras,DataDog/integrations-extras,DataDog/integrations-extras,DataDog/integrations-extras,DataDog/integrations-extras