How do I change the Version number of the parent app?

When I try to validate my sticker pack app for distribution I keep getting this error:

"CFBundleShortVersionString of an app extension ('1.2.0') must match that of its containing parent app ('1.0.1')"

I want the version number to be 1.2.0. I can't seem to change this parent app version number. How do I access the "parent app"?

I've tried changing the Version number under General Tab, as well as the Versioning section under Build Settings.

Any help much appreciated.