Ensure the license tool jar name contains no classifier suffix.
Ensure the license tool jar name contains no classifier suffix.

Since Gradle 5.1, the classifier is null and thus the shadowJar tool
will create a JAR without any classifier suffix.
By setting the `classifier` to null explicit, the output JAR name
of the licensing tool will always be the same.

crate/crate,EvilMcJerkface/crate,crate/crate,EvilMcJerkface/crate,crate/crate,EvilMcJerkface/crate