Fix CDN links. (#6426)
Fix CDN links. (#6426)

Update to match CDN instructions from README.md.
ReactiveX/RxJS,martinsik/rxjs,ReactiveX/RxJS,martinsik/rxjs,ReactiveX/rxjs,martinsik/rxjs,martinsik/rxjs,ReactiveX/RxJS,ReactiveX/RxJS,ReactiveX/rxjs,ReactiveX/rxjs,ReactiveX/rxjs