Downloading scheme.json fails with specific command usage

Is it expected behavior to fail downloading `scheme.json` depending on the order of the options?

```
// Success
apollo schema:download --endpoint= /schema.json --header=
✔ Loading Apollo Project
✔ Saving schema to /schema.json

// Failed
apollo schema:download --endpoint= --header= /schema.json
✔ Loading Apollo Project
✖ Saving schema to /schema.json
→ Header name must be a valid HTTP Token [""]
TypeError: Header name must be a valid HTTP Token [""]
```