Update step-2.mdx

src/pages/developing/react-tutorial/step-2.mdx

@@ -113,7 +113,7 @@ the `sm`, `md`, and `lg` props. For example, `<Column sm={2} md={8} lg={8}/>`
 means the column will span 2/4 columns at the small breakpoint, 8/8 columns at
 the medium breakpoint, 8/16 columns at the large breakpoint.
 
-We've included the designs for this tutorial app in the `design.sketch` file
+We've included the designs for this tutorial app in the `design.figma` file
 found as a top-level file in the `carbon-tutorial` repository. But, if you don't
 have Sketch installed and available to inspect the design, we'll provide
 screenshots.