If you installed the app directly from pokemmo.eu, this is likely a false positive. AVG probably doesn't like the fact that it is a sideloaded app, combined with being brand new from an update.
I've submitted the current client to AVG to review. You can either wait for this to go away (Click Resolve, which will uninstall the app, and then reinstall it later when this is resolved) or click ignore to ignore the detection.