Reduce cancel/done button font weight

packages/@uppy/dashboard/src/style.scss

@@ -406,7 +406,7 @@
 .uppy-DashboardContent-back {
   @include reset-button;
   font-size: 14px;
-  font-weight: 500;
+  font-weight: 400;
   cursor: pointer;
   color: $color-cornflower-blue;
 }