Update no-system-props.js

Author: colebemis

src/rules/no-system-props.js

@@ -17,7 +17,8 @@ const excludedComponentProps = new Map([
   ['Dialog', new Set(['width', 'height'])],
   ['ProgressBar', new Set(['bg'])],
   ['Spinner', new Set(['size'])],
-  ['StyledOcticon', new Set(['size'])]
+  ['StyledOcticon', new Set(['size'])],
+  ['PointerBox', new Set(['sx'])],
 ])
 
 const alwaysExcludedProps = new Set(['variant'])