docs: add alexanderchan as a contributor (#171)

* docs: update README.md

* docs: update .all-contributorsrc

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>

Author: allcontributors[bot]

.all-contributorsrc

@@ -274,6 +274,15 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "alexanderchan",
+      "name": "Alex Chan",
+      "avatar_url": "https://avatars.githubusercontent.com/u/1864372?v=4",
+      "profile": "https://twitter.com/alexandermchan",
+      "contributions": [
+        "doc"
+      ]
     }
   ]
 }