fix(tabbar): add default height (#1701)

src/packages/__VUE/tabbar/index.scss

@@ -10,7 +10,8 @@
   border-top: $tabbar-border-top;
   width: 100%;
   display: flex;
-  padding: 7px 0;
+  align-items: center;
+  height: 50px;
   box-sizing: border-box;
   background: $white;