pdoc3 crashes after package 'pdoc' is uninstalled

This issue is probably the same as #30 which was closed "invalid". Here are steps to reproduce.

It looks like an interaction (name collision) between "pdoc" and "pdoc3" packages. Both packages appear to create this file upon install and remove it upon uninstall:

Lib/site-packages/pdoc/__init__.py

Expected Behavior

> pdoc3 --version
pdoc3 0.7.2

Actual Behavior

> pdoc3 --version
Traceback (most recent call last):
  File "C:\Python36-32\Scripts\pdoc3-script.py", line 11, in <module>
    load_entry_point('pdoc3==0.7.2', 'console_scripts', 'pdoc3')()
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 476, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 2700, in load_entry_point
    return ep.load()
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 2318, in load
    return self.resolve()
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 2324, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "c:\python36-32\lib\site-packages\pdoc\cli.py", line 27, in <module>
    '--version', action='version', version='%(prog)s ' + pdoc.__version__)
AttributeError: module 'pdoc' has no attribute '__version__'

Steps to Reproduce

1. Clean slate

> pip3 uninstall pdoc pdoc3 markdown

2. Install pdoc3 to observe normal behaviour

> pip3 install pdoc3

3. Observe normal behaviour

> pdoc3 --version
pdoc3 0.7.2

4. SOURCE OF ISSUE - Install pdoc and then uninstall (which downgrades markdown, so we need to re-upgrade that):

> pip3 install pdoc
> pip3 uninstall pdoc
> pip3 install --upgrade markdown

5. Observe crash:

> pdoc3 --version
Traceback (most recent call last):
  File "C:\Python36-32\Scripts\pdoc3-script.py", line 11, in <module>
    load_entry_point('pdoc3==0.7.2', 'console_scripts', 'pdoc3')()
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 476, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 2700, in load_entry_point
    return ep.load()
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 2318, in load
    return self.resolve()
  File "c:\python36-32\lib\site-packages\pkg_resources\__init__.py", line 2324, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "c:\python36-32\lib\site-packages\pdoc\cli.py", line 27, in <module>
    '--version', action='version', version='%(prog)s ' + pdoc.__version__)
AttributeError: module 'pdoc' has no attribute '__version__'

Workaround

Uninstall pdoc and pdoc3 and re-install pdoc3.

> pip3 uninstall pdoc pdoc3
> pip3 install pdoc3

Additional info

• pdoc3 version: 0.7.2
• Python 3.7.4
• Windows 10 command line

Start with the traceback location in pdoc/cli.py and reproduce the package-install sequence on Python 3.7.4 and Windows if available. Compare the pdoc3 and pdoc installations around Lib/site-packages/pdoc/init.py, then verify that pdoc3 --version still reports pdoc3 0.7.2 after pdoc is installed and uninstalled.