[apitools] When a method is added to a baseclass the package version must be increased

[laeubi]

It was recently discovered that API tools seem to not discover a case where a package version increment is required.

• We have the attached testcase here example.zip
• Lib1 contains the baseline where we have package p + q in version 1
• Lib2 is the bundle we like to compare against the baseline and where we have added a new method to A that is inherited by B
• In the Manifest we have already incremented the version for package p but the version increment for q is missing

Currently API tools seem to not discover this case but e.g. tycho-baseline plugin does detect it as a required change as demonstrated with a recently added test-case here.

FYI @stephan-herrmann