feat(lib): add gridColor param

src/container/GraphView/index.js

@@ -17,7 +17,7 @@ const GraphView = memo(({
   nodeTypes, edgeTypes, onMove, onLoad,
   onElementClick, onNodeDragStop, connectionLineType, connectionLineStyle,
   selectionKeyCode, onElementsRemove, deleteKeyCode, elements,
-  onConnect
+  onConnect, gridColor
 }) => {
   const zoomPane = useRef();
   const rendererNode = useRef();
@@ -68,7 +68,7 @@ const GraphView = memo(({
 
   return (
     <div className="react-flow__renderer" ref={rendererNode}>
-      <GridRenderer />
+      <GridRenderer strokeColor={gridColor} />
       <NodeRenderer
         nodeTypes={nodeTypes}
         onElementClick={onElementClick}