docs: add xujenna as a contributor (#471)

* docs: update README.md

* docs: update .all-contributorsrc

Author: allcontributors[bot]

.all-contributorsrc

@@ -528,6 +528,15 @@
       "contributions": [
         "ideas"
       ]
+    },
+    {
+      "login": "xujenna",
+      "name": "Jenna",
+      "avatar_url": "https://avatars2.githubusercontent.com/u/13280722?v=4",
+      "profile": "http://www.xujenna.com",
+      "contributions": [
+        "ideas"
+      ]
     }
   ],
   "contributorsPerLine": 7,