git.diff test resource is in the wrong package

[detouched]

git.diff test resource is located under org/wickedsource/diffparser/unified/, whereas the GitDiffTest class which uses it has been moved at b6df332 to io.reflectoring.diffparser.unified, so it is now failing due to resource load error.

[javydreamercsw]

Looks like this can be closed with a PR.