[Docs] Issue when publishing schema

Hey there!
For some reason when trying to [publish the schema](https://www.apollographql.com/docs/tutorial/production.html#publish) I was getting this error:
```
✔ Loading Apollo Project
✖ Uploading service to Engine
→ No service found to link to Engine
Error: No service found to link to Engine
at Task.task (~/.npm/_npx/32532/lib/node_modules/apollo/lib/commands/service/push.js:17:31)
at Promise.resolve.then.then.skipped (~/.npm/_npx/32532/lib/node_modules/apollo/node_modules/listr/lib/task.js:167:30)
at
```

This is what I did, and didn't work:
- Had my `.env` file with the `ENGINE_API_KEY` set.
- Tried removing the `sevice:` prefix from the value of the variable
- Tried restarting the server
- Tried running `npx apollo service:check && npx apollo service:push` from the `/server` folder
- Double and tripled checked the API key

Finally I gave up and had to type the parameters directly on the `service:push` command.

Is this only my issue?

Comienza con las instrucciones de publicación en producción enlazadas en el issue y la configuración de `/server`; después, reproduce los comandos `npx apollo service:check` y `service:push` usando `.env` y `ENGINE_API_KEY`. Se considera terminado cuando funciona el flujo de publicación del esquema documentado en el tutorial o las instrucciones explican claramente los parámetros y la configuración necesarios.

Escrito por el modelo de indexación a partir del texto del issue.