message: FlexProps should extend BoxProps
diff: @@ -74,7 +74,8 @@ declare module '@primer/components' {
  StyledSystem.AlignContentProps,
  StyledSystem.AlignItemsProps,
  StyledSystem.JustifyContentProps,
  - StyledSystem.JustifyItemsProps {}
  + StyledSystem.JustifyItemsProps,
  + BoxProps {}
  export const Flex: React.FunctionComponent<FlexProps> & {
  Item: React.FunctionComponent<FlexItemProps>
  