bump the difficulty

Author: glennj

config.json

@@ -282,14 +282,6 @@
         "prerequisites": [],
         "difficulty": 3
       },
-      {
-        "slug": "gigasecond",
-        "name": "Gigasecond",
-        "uuid": "f870722b-6bfc-4516-92ba-9fb1c2866d34",
-        "practices": [],
-        "prerequisites": [],
-        "difficulty": 3
-      },
       {
         "slug": "high-scores",
         "name": "High Scores",
@@ -642,6 +634,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "gigasecond",
+        "name": "Gigasecond",
+        "uuid": "f870722b-6bfc-4516-92ba-9fb1c2866d34",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "matching-brackets",
         "name": "Matching Brackets",