【bug】代码缺少 rgb += ")",导致ie11中不能正常处理这种错误

review by yangtt

Author: yuzhiyao

src/openlayers/core/StyleUtils.js

@@ -953,6 +953,7 @@ export class StyleUtils {
         index === 3 ? rgb += color : rgb += color + ',';
       });
     }
+    rgb += ")"
     return rgb;
   }