grommet pack does not consider .env file contents

[thg303]

how to reproduce:

1. build a new project.
2. create a .env file and set a variable in it like:

PORT=5050

3. run npm run dev
   it serves it on the default port (3000).

the expected behaviour is serving the app on http://localhost:5050

[thg303]

looks like babel puts imports statements above 'require`s so the pack scrip loads before dotenv has any chance to load the .env file.