Currently, packages in coverme without tests created by student
are not checked for coverage, because no there are no test targets
for them at all!
The issue can be fixed by simply creating empty !change files,
but we are engineers, aren't we? :)
Bonus point: it prevents new packages from giving false coverage credit.
For example, mock file generated by gomock will have lots of covered code
almost instantly. However, the task can be hacked by adding new code to
existing packages.
