Adds SIG meeting information to README (open-telemetry#30)

Author: bg451

README.md

@@ -9,3 +9,5 @@ Community Channel: [![Gitter chat][main-gitter-image]][main-gitter-url]
 [main-gitter-url]: https://gitter.im/open-telemetry/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge
 [node-gitter-image]: https://badges.gitter.im/open-telemetry/opentelemetry-node.svg
 [node-gitter-url]: https://gitter.im/open-telemetry/opentelemetry-node?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge
+
+We have a weekly SIG meeting! See the [community page](https://github.com/open-telemetry/community#nodejs-sdk) for meeting details and notes.