Update Greedy_Sorting.problems.json

Author: Pramad712

content/3_Silver/Greedy_Sorting.problems.json

@@ -205,7 +205,7 @@
       "name": "IPO",
       "url": "https://leetcode.com/problems/ipo",
       "source": "LC",
-      "difficulty": "Medium",
+      "difficulty": "Normal",
       "isStarred": false,
       "tags": ["Greedy", "Sorting", "Priority Queue"],
       "solutionMetadata": {