feat: udpate fetch-rs

__network/fetch-rs/README.md

@@ -22,12 +22,12 @@ let response = fetch(
     "https://hatter.ink/util/print_request.action",
     &FetchOptions {
         method: FetchMethod::Post,
-        headers: Some(vec![
+        headers: vec![
             FetchHeader {
                 key: "content-type".to_string(),
                 value: "application/json".to_string(),
             }
-        ]),
+        ],
         body: Some("{}".as_bytes().to_vec()),
         ..Default::default()
     })?;