fix path

Author: bodewig

src/main/net-core/XMLUnit.Core.nuspec

@@ -26,6 +26,6 @@
     <file src="..\..\..\build/bin/Release/netstandard2.0/xmlunit-core.dll" target="lib\netstandard2.0"/>
     <file src="..\..\..\build/bin/Release/netstandard2.0/xmlunit-core.pdb" target="lib\netstandard2.0"/>
     <file src="..\..\..\build/bin/Release/netstandard2.0/xmlunit-core.xml" target="lib\netstandard2.0"/>
-    <file src="..\..\docs/readmes/xmlunit-core/README.md" target="docs"/>
+    <file src="..\..\doc/readmes/net-core/README.md" target="docs"/>
   </files>
 </package>