Fix HMCL-dev#619

Author: huanghongxun

HMCLCore/src/main/java/org/jackhuang/hmcl/util/io/NetworkUtils.java

@@ -178,7 +178,7 @@ public static String readData(HttpURLConnection con) throws IOException {
     public static String detectFileName(URL url) throws IOException {
         HttpURLConnection conn = resolveConnection(createConnection(url));
         int code = conn.getResponseCode();
-        if (code == 404)
+        if (code / 100 == 4)
             throw new FileNotFoundException();
         if (code / 100 != 2)
             throw new IOException(url + ": response code " + conn.getResponseCode());