Don't downgrade Current Version Code during updatecheck
It occasionally happends that the recommended version gets downgraded by the update check bot. This can happen for various reaseons:
- a build was manually added and marked as CV
- something changed in the upstream repo
- something changed in fdroidserver code
I think this is never a useful feature. Sometimes we want to add a stable build which cannot yet be picked up by UCM. But this might be fixed by upstream later and disabling UCM until then is not a good idea, because this would deprive us of all further update notifications.
So I propose to only process the update when the versionCode increases.
I assume sometimes it is necessary to downgrade the CV of an app, but I think this never needs to happen automatically.