Add LC 504 IPO to Silver Greedy

Author: Pramad712

content/3_Silver/Greedy_Sorting.problems.json

@@ -200,6 +200,18 @@
         "kind": "internal"
       }
     },
+    {
+      "uniqueId": "lc-IPO",
+      "name": "IPO",
+      "url": "https://leetcode.com/problems/ipo",
+      "source": "LC",
+      "difficulty": "Medium",
+      "isStarred": false,
+      "tags": ["Greedy", "Sorting", "Priority Queue"],
+      "solutionMetadata": {
+        "kind": "none"
+      }
+    },  
     {
       "uniqueId": "usaco-990",
       "name": "Berry Picking",