fix url setting

Author: Scott Lepper

src/components/ConfigEditor.tsx

@@ -43,8 +43,9 @@ export class ConfigEditor extends PureComponent<Props, State> {
     const jsonData = { ...state.jsonData, ...option };
 
     const { onOptionsChange, options } = this.props;
+    const opt = {...options, url: option.url || options.url};
     onOptionsChange({
-      ...options,
+      ...opt,
       jsonData,
     });