Added An Interactive PlayGround For React (#10578)

Co-authored by: Eric Hellman <eric@hellman.net>

more/free-programming-playgrounds.md

@@ -299,6 +299,7 @@
 * [CodeSandbox.io](https://codesandbox.io)
 * [Hello React - (Glitch)](https://glitch.new/react) *(Account requested, not required)*
 * [jscomplete](https://jscomplete.com/playground)
+* [PlayCode](https://playcode.io/react)
 * [StackBlitz](https://stackblitz.com/fork/react)