list-ops: add append case (#1612)

* Add case to append empty list to list

* Add UUID

Co-authored-by: wolf99 <wol99@users.noreply.github.com>

Author: wolf99

exercises/list-ops/canonical-data.json

@@ -29,6 +29,16 @@
           },
           "expected": [1, 2, 3, 4]
         },
+        {
+          "uuid": "e842efed-3bf6-4295-b371-4d67a4fdf19c",
+          "description": "empty list to list",
+          "property": "append",
+          "input": {
+            "list1": [1, 2, 3, 4],
+            "list2": []
+          },
+          "expected": [1, 2, 3, 4]
+        },
         {
           "uuid": "71dcf5eb-73ae-4a0e-b744-a52ee387922f",
           "description": "non-empty lists",