docs: update playground link

Playground has been updated with latest Angular 17 with more perf improvements.

The new Playground also fetches `super-expressive` repo for the latest `d.ts` instead of storing an asset so it should stay up-to-date.

I might add a dropdown for version selection if people ask for it.

readme.md

@@ -132,7 +132,7 @@ const myRegex = SuperExpressive()
 
 ## Playground
 
-You can experiment with `SuperExpressive` in the [Super Expressive Playground](https://sepg.netlify.app/) by [@nartc](https://github.com/nartc). This is a great way to build a regex description, and test it against various inputs.
+You can experiment with `SuperExpressive` in the [Super Expressive Playground](https://nartc.github.io/ng-super-expressive/) by [@nartc](https://github.com/nartc). This is a great way to build a regex description, and test it against various inputs.
 
 <img src="playground-small.jpg">