Added package packedjson (#749)

packages.json

@@ -9400,6 +9400,17 @@
     "license": "ISC",
     "web": "https://github.com/jackvandrunen/findtests"
   },
+  {
+    "name": "packedjson",
+    "url": "https://github.com/Araq/packedjson",
+    "method": "git",
+    "tags": [
+      "json"
+    ],
+    "description": "packedjson is an alternative Nim implementation for JSON. The JSON is essentially kept as a single string in order to save memory over a more traditional tree representation.",
+    "license": "MIT",
+    "web": "https://github.com/Araq/packedjson"
+  },
   {
     "name": "unicode_numbers",
     "url": "https://github.com/Aearnus/unicode_numbers",