docs: update .all-contributorsrc [skip ci]

allcontributors[bot] · web-flow · commit 8b4de3018ea4 · 2020-03-25T22:31:52.000Z
diff --git a/.all-contributorsrc b/.all-contributorsrc
@@ -13,7 +13,8 @@
       "contributions": [
         "code",
         "doc",
-        "example"
+        "example",
+        "maintenance"
       ]
     }
   ],
