Merge pull request #1799 from hsldymq/fix-fade-transition

fix(Transition): fade-transition淡出淡入无效

src/design/transition/fade.less

@@ -1,3 +1,15 @@
+.fade-transition {
+  &-enter-active,
+  &-leave-active {
+    transition: opacity 0.2s ease-in-out;
+  }
+
+  &-enter-from,
+  &-leave-to {
+    opacity: 0;
+  }
+}
+
 .fade-enter-active,
 .fade-leave-active {
   transition: opacity 0.2s ease-in-out;