docs: add b2renger as a contributor (#468)

* docs: update README.md

* docs: update .all-contributorsrc

Author: allcontributors[bot]

.all-contributorsrc

@@ -500,6 +500,16 @@
         "maintenance",
         "example"
       ]
+    },
+    {
+      "login": "b2renger",
+      "name": "b2renger",
+      "avatar_url": "https://avatars2.githubusercontent.com/u/1818874?v=4",
+      "profile": "http://b2renger.github.io/",
+      "contributions": [
+        "code",
+        "infra"
+      ]
     }
   ],
   "contributorsPerLine": 7,