Update README.md

[JayHoltslander]

Congrats. :-)

[boynet]

Congrats 👍
a little question they said "it uses the highly performant Intersection Observer API (where available)" is it true? from what I see still no Intersection Observer in https://github.com/aFarkas/lazysizes/blob/gh-pages/lazysizes.js

[aFarkas]

@boynet
You can use https://github.com/aFarkas/lazysizes/blob/gh-pages/src/lazysizes-intersection.js if you really want to use intersection observer (You will either need to add a polyfill or conditionally load one of both scripts for non supporting browsers). From my experience it won't give you a noticeable performance gain to the normal version because this one is highly optimized.

In a world where you don't need to polyfill it it would be a simple go to because the API is quite helpful to create a lazyloader.