Update type hint in Graph.__init__

A type hint for edges parameter in Graph constructor was wrong, as it has to be a List of Lists. The current List of Sets would fail on the attempts to subscript the Set members.

Author: comp64

pathfinding/core/graph.py

@@ -4,7 +4,7 @@
 
 class Graph:
     def __init__(
-            self, edges: List[Set] = None, nodes: Dict[int, GraphNode] = None,
+            self, edges: List[List] = None, nodes: Dict[int, GraphNode] = None,
             bi_directional: bool = False):
         # edges defined by node-from, node-to and its cost
         self.edges = edges if edges else []