Update link in readme [skip ci]

README.md

@@ -121,5 +121,5 @@ Thanks to these people for their work on [the original polyfill][creatorrr-polyf
 [ref-impl-transferarraybuffer]: https://github.com/whatwg/streams/blob/cada8129edcc4803b2878a7a3f5e1d8325dc0c23/reference-implementation/lib/abstract-ops/ecmascript.js#L16
 [issue-3]: https://github.com/MattiasBuelens/web-streams-polyfill/issues/3
 [wpt-async-iterator-prototype]: https://github.com/web-platform-tests/wpt/blob/87a4c80598aee5178c385628174f1832f5a28ad6/streams/readable-streams/async-iterator.any.js#L24
-[stub-async-iterator-prototype]: https://github.com/MattiasBuelens/web-streams-polyfill/blob/v3.1.0/src/target/es5/stub/async-iterator-prototype.ts
+[stub-async-iterator-prototype]: https://github.com/MattiasBuelens/web-streams-polyfill/blob/next/src/lib/readable-stream/async-iterator.ts#L153-L161
 [creatorrr-polyfill]: https://github.com/creatorrr/web-streams-polyfill