display error if hardcoded versions are detected in world file
an issue was reported in chat where the upgrade script / apk failed to upgrade the system due to some dependency conflicts. Turns out that the user had megapixels=1.5.2-r0
in their apk world file. apk's output was not helpful at all in troubleshooting this problem (it was a massive dep conflict with many libraries / apps). I think it would be helpful if the upgrade script printed an error or something before trying to upgrade if it detects any lines in the world file that indicate a version was hard-coded, since I think that'll almost certainly result in these hard-to-debug dep conflicts from apk.