Fix inline search in Safari

This closes https://github.com/select2/select2/issues/3459
This closes https://github.com/select2/select2/pull/3476

src/scss/theme/default/layout.scss

@@ -28,6 +28,7 @@
       border: none;
       outline: 0;
       box-shadow: none;
+      -webkit-appearance: textfield;
     }
   }