docs: update .all-contributorsrc [skip ci]

allcontributors[bot] · web-flow · commit 0793ae766e00 · 2021-08-08T11:00:10.000Z
diff --git a/.all-contributorsrc b/.all-contributorsrc
@@ -13,7 +13,8 @@
       "contributions": [
         "code",
         "bug",
-        "doc"
+        "doc",
+        "maintenance"
       ]
     }
   ],
