fix(ui): list item hover background more subtle

Author: Guillaume Chau

packages/@vue/cli-ui/src/style/mixins.styl

@@ -6,7 +6,7 @@ list-item()
     background rgba($vue-ui-color-primary, .05)
 
   &:hover
-    background rgba($vue-ui-color-primary, .1)
+    background rgba($vue-ui-color-primary, .03)
 
 
 ansi-colors($name, $color)