fix(readme): Correct urls to npm (#1144)

Apparent copy/paste error pointed to instrumentation-dns instead of
instrumentation-express

Co-authored-by: Amir Blum <amir@aspecto.io>

plugins/node/opentelemetry-instrumentation-express/README.md

@@ -148,5 +148,5 @@ 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-dns
-[npm-img]: https://badge.fury.io/js/%40opentelemetry%2Finstrumentation-dns.svg
+[npm-url]: https://www.npmjs.com/package/@opentelemetry/instrumentation-express
+[npm-img]: https://badge.fury.io/js/%40opentelemetry%2Finstrumentation-express.svg