'NoneType' object has no attribute 'group'

## Library version

*What's the installed library version ? Check with `instalooter --version`*:

```
instalooter v2.0.3
```

## Environment

*Describe here your environment, including:*

* Debian 9 Stretch
* Python 3.5.3

## Error description - runtime

When I trying to login to Instagram with instalooter, instalooter asks for 'Username' and 'Password'. It doesn't login and throws the following error:
CRITICAL 'NoneType' object has no attribute 'group'
WARNING unclosed

*If you have an issue at runtime, include the required information below:*

### Reproducible test case

```
instalooter login
```

### Expected behaviour

instalooter logs into Instagram and returns to the prompt after asking for my Username and Password

### Actual behaviour

Asks for Username and Password and then throws the following error:

**CRITICAL** 'NoneType' object has no attribute 'group'
**WARNING** unclosed

### Traceback

Traceback (most recent call last):
File "/home/acloserview/.local/lib/python3.5/site-packages/instalooter/cli/__init__.py", line 104, in main
login(args)
File "/home/acloserview/.local/lib/python3.5/site-packages/instalooter/cli/login.py", line 22, in login
InstaLooter._login(username, password)
File "/home/acloserview/.local/lib/python3.5/site-packages/instalooter/looters.py", line 143, in _login
token = get_shared_data(login.text)['config']['csrf_token']
File "/home/acloserview/.local/lib/python3.5/site-packages/instalooter/_utils.py", line 94, in get_shared_data
return json.loads(match.group(1))
AttributeError: 'NoneType' object has no attribute 'group'