fix(handle): pass className

dist/ReactGraph.js

@@ -32910,7 +32910,7 @@
         target = _ref.target,
         rest = _objectWithoutProperties(_ref, ["source", "target"]);
 
-    var handleClasses = classnames('react-graph__handle', {
+    var handleClasses = classnames('react-graph__handle', rest.className, {
       source: source,
       target: target
     });

src/NodeRenderer/HandleTypes/BaseHandle.js

@@ -10,6 +10,7 @@ function onDragStart(evt, nodeId) {
 export default memo(({ source, target, ...rest }) => {
   const handleClasses = cx(
     'react-graph__handle',
+    rest.className,
     { source, target }
   );