Library plugin should add dependency on core library using major .+

[wakingrufus]

The plugin should add dependencies on the core library of the same version. However, there are 2 edge cases:

1. tests, where jar packaging with a version has not been done
2. the core library is published to maven central, whereas the plugin is published to Gradle Plugin Portal. Maven central has a much longer delay, so for a while, there is a state where the plugin is available, but the corresponding core library is not yet available. In this case, we can match to the latest version of the same major version, which will solve the problem for any users who use dynamic minor or patch versions.