chore(stepper): add changeset

Author: marissahuysentruyt

.changeset/sharp-spiders-complain.md

@@ -0,0 +1,6 @@
+---
+"@spectrum-css/stepper": patch
+---
+
+- Updates `--spectrum-stepper-border-color-focus-hover` from `gray-800` to `gray-900`.
+- Updates `--spectrum-stepper-buttons-border-color-keyboard-focus` from `gray-900` to `gray-800` to match the rest of the border color on keyboardFocus.