Rename Zip::ZipFile class
Rename Zip::ZipFile class

This changed when we replace zip gem with rubyzip [1] upstream.

Fixes: https://github.com/mysociety/alaveteli/issues/6014

[1] https://github.com/mysociety/alaveteli/commit/1ca4f53

mysociety/ipvtheme,mysociety/ipvtheme