Merge pull request exercism#798 from RollandMichael7/patch-1

Add Isogram topics

Author: FridaTveit

config.json

@@ -227,7 +227,12 @@
       "core": false,
       "difficulty": 4,
       "slug": "isogram",
-      "topics": null,
+      "topics": [
+        "conditionals",
+        "loops",
+        "strings",
+        "parsing"
+      ],
       "unlocked_by": "hello-world",
       "uuid": "c3e89c7c-3a8a-4ddc-b653-9b0ff9e1d7d8"
     },