Fix the code font stack /cc @kvz

Using the same as seen on GitHub

website/themes/uppy/source/css/_settings.scss

@@ -1,7 +1,7 @@
 // font faces
 $fontFamily-body : 'PT Root UI', 'Helvetica Neue', Arial, sans-serif;
 $fontFamily-logo : 'PT Root UI', 'Helvetica Neue', Arial, sans-serif;
-$fontFamily-code : 'Roboto Mono', Menlo, Monaco, courier, monospace;
+$fontFamily-code : 'SFMono-Regular', 'Consolas', 'Liberation Mono', 'Menlo', Courier, monospace;
 
 // font sizes
 $fontSize-body : 16px;