Add __main__.py to enable python -m pypinfo

[hugovk]

This allows you to easily specify which interpreter to use:

pypinfo --percent -d 1 pillow
python -m pypinfo --percent -d 1 pillow
python3.11 -m pypinfo --percent -d 1 pillow

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (792a4ef) to head (b58c1cd).

Additional details and impacted files

@@            Coverage Diff            @@
##            master      #156   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            6         6           
  Lines          546       546           
  Branches        74        74           
=========================================
  Hits           546       546           

Flag	Coverage Δ
macOS-latest	100.00% <ø> (ø)
ubuntu-latest	100.00% <ø> (ø)
windows-latest	100.00% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ofek]

Definitely an oversight, thank you!