Missing requirement (pkginfo)?

# How it happened

Calling `extrapypi start --filename extrapypi-config.cfg` immediatly after installing caused this error:

```python
Traceback (most recent call last):
File "/home/user/miniconda3/envs/myenv/bin/extrapypi", line 6, in
from extrapypi.manage import cli
File "/home/user/miniconda3/envs/myenv/lib/python3.7/site-packages/extrapypi/manage.py", line 5, in
from extrapypi.app import create_app
File "/home/user/miniconda3/envs/myenv/lib/python3.7/site-packages/extrapypi/app.py", line 31, in
from extrapypi import simple, utils, dashboard, user
File "/home/user/miniconda3/envs/myenv/lib/python3.7/site-packages/extrapypi/simple/__init__.py", line 1, in
from . import views
File "/home/user/miniconda3/envs/myenv/lib/python3.7/site-packages/extrapypi/simple/views.py", line 18, in
from extrapypi.commons.packages import create_release, get_store
File "/home/user/miniconda3/envs/myenv/lib/python3.7/site-packages/extrapypi/commons/packages.py", line 11, in
from extrapypi import storage
File "/home/user/miniconda3/envs/myenv/lib/python3.7/site-packages/extrapypi/storage/__init__.py", line 9, in
from .local import LocalStorage
File "/home/user/miniconda3/envs/myenv/lib/python3.7/site-packages/extrapypi/storage/local.py", line 12, in
import pkginfo
ModuleNotFoundError: No module named 'pkginfo'
```

When I installed `pkginfo` it worked.

# My environment

* WSL (Windows, -> Linux-Emulation)
* Conda-Environment

# Solution

Include `pkginfo` into `install_requires` of the `setup.py`. It is already in the `requirements.txt` file.

Compare the dependencies in setup.py with requirements.txt, focusing on the missing pkginfo entry reported by the installation traceback. Verify the package can start after installation with `extrapypi start --filename extrapypi-config.cfg`, and confirm pkginfo is included in the install requirements.

Written by the indexing model from the issue text.