**Apache Airflow version**: 2.0.0b2

**What happened**:

Starting in 2.0.0b2, extras that aren't also providers like `statsd` prevents Airflow from being installed.

**How to reproduce it**:
```
$ docker run --rm -ti python:3.6 bash
# pip install apache-airflow[statsd]==2.0.0b2
Collecting apache-airflow[statsd]==2.0.0b2                 
  Downloading apache_airflow-2.0.0b2-py3-none-any.whl (4.5 MB)                    
...
Collecting statsd<4.0,>=3.3.0; extra == "statsd"          
  Downloading statsd-3.3.0-py2.py3-none-any.whl (11 kB)
ERROR: Could not find a version that satisfies the requirement apache-airflow-providers-statsd; extra == "statsd" (from apache-airflow[statsd]==2.0.0b2) (from versions: none)         
ERROR: No matching distribution found for apache-airflow-providers-statsd; extra == "statsd" (from apache-airflow[statsd]==2.0.0b2)
```

I believe this is from https://github.com/apache/airflow/pull/12233
setup.py
'psutil>=4.2.0, <6.0.0',
    'pygments>=2.0.1, <3.0',
    'python-daemon>=2.1.1',
    'python-dateutil>=2.3, <3',
    'python-nvd3~=0.15.0',
    'python-slugify>=3.0.0,<5.0',
    'requests>=2.20.0, <3',
    'rich==9.2.0',
    'setproctitle>=1.1.8, <2',
    'sqlalchemy>=1.3.18, <2',
    'sqlalchemy_jsonfield~=0.9',
    'tabulate>=0.7.5, <0.9',
    'tenacity~=6.2.0',
    'termcolor>=1.1.0',
    'thrift>=0.9.2',
    'typing;python_version<"3.6"',
    'typing-extensions>=3.7.4;python_version<"3.8"',
    'tzlocal>=1.4,<2.0.0',
    'unicodecsv>=0.14.1',
    'werkzeug~=1.0, >=1.0.1',
]
def get_provider_package_from_package_id(package_id: str):
    """
    Builds the name of provider package out of the package id provided/
    :param package_id: id of the package (like amazon or microsoft.azure)
    :return: full name of package in PyPI
    """
    package_suffix = package_id.replace(".", "-")
    return f"apache-airflow-providers-{package_suffix}"
def do_setup():