Add example of using dotenv with nestjs

Author: motdotla

README.md

@@ -94,6 +94,7 @@ See [examples](https://github.com/dotenv-org/examples) of using dotenv with vari
 * [react](https://github.com/dotenv-org/examples/tree/master/dotenv-react)
 * [react (typescript)](https://github.com/dotenv-org/examples/tree/master/dotenv-react-typescript)
 * [express](https://github.com/dotenv-org/examples/tree/master/dotenv-express)
+* [nestjs](https://github.com/dotenv-org/examples/tree/master/dotenv-nestjs)
 
 ## Documentation