Merge pull request #246 from zjyau/v2-dev

fix: 修复nut-elevator嵌套Popup或ActionSheet中,iOS端不显示问题

src/packages/elevator/elevator.scss

@@ -1,5 +1,5 @@
 .nut-elevator{
-    position: fixed;
+    position:relative;
     top:40px;
     width: 100%;
 }