If you have already integrated the plugin and want to upgrade it
to a newer version,you must delete the Assets/GooglePlayGames
folder, then import the new package.
SPECIAL NOTICE: Some of the files in this release were moved
from Assets/Editor toAssets/GooglePlayGames/Editor. Unity sometimes
does not detect these files as changed files.To fix this, import
the package a second time if you have compiliation errors in
scripts located inAssets/GooglePlayGames/Editor.
After upgrading, redo setup (click "Google Play Games | Android
Setup" and/or "Google Play Games | iOS Setup" on the menu). Do this
even if you had already donethis before on this project.
