modernize v0.5-0.7 Release Notes

    • โž• Added the opt-in classic_division fixer.
    • โšก๏ธ Updated the dict_six fixer to support six.viewitems() and friends.
    • ๐Ÿ†• New fixer for unichr, changed to six.unichr.
    • ๐Ÿ“š Documentation corrections.