main/py3-zipp: upgrade to 3.4.0
community/py3-importlib-metadata depends on it but has been merged to the standard lib of Python 3.8 and is thus unnecessary.
The only left-over dep is
community/py3-importlib-resources but that has been merged in the Python standard lib for 3.9 so can be dropped too when that hits the Alpine repos. At that point we can drop this package entirely.