docs(undici): Fix NPM badge in README.md. (#2235)

Author: mattcollier

plugins/node/instrumentation-undici/README.md

@@ -100,5 +100,5 @@ Apache 2.0 - See [LICENSE][license-url] for more information.
 [discussions-url]: https://github.com/open-telemetry/opentelemetry-js/discussions
 [license-url]: https://github.com/open-telemetry/opentelemetry-js-contrib/blob/main/LICENSE
 [license-image]: https://img.shields.io/badge/license-Apache_2.0-green.svg?style=flat
-[npm-url]: https://www.npmjs.com/package/@opentelemetry/instrumentation-router
-[npm-img]: https://badge.fury.io/js/%40opentelemetry%2Finstrumentation-router.svg
+[npm-url]: https://www.npmjs.com/package/@opentelemetry/instrumentation-undici
+[npm-img]: https://badge.fury.io/js/%40opentelemetry%2Finstrumentation-undici.svg