run-length-encoding: estimate difficulty 5

config.json

       ]
     },
     {
+      "slug": "run-length-encoding",
+      "difficulty": 5,
+      "topics": [
+
+      ]
+    },
+    {
       "slug": "robot-name",
       "difficulty": 5,
       "topics": [
       "topics": [
 
       ]
-    },
-    {
-      "slug": "run-length-encoding",
-      "difficulty": 1,
-      "topics": [
-
-      ]
     }
   ],
   "deprecated": [