message: add missing header type
diff: @@ -312,6 +312,8 @@ declare module '@primer/components' {
  export interface SelectMenuDividerProps extends CommonProps, Omit<React.HTMLAttributes<HTMLDivElement>, 'color'> {}
  + export interface SelectMenuHeaderProps extends CommonProps, TypographyProps, Omit<React.HTMLAttributes<HTMLElement>, 'color'> {}
  +
  export interface SelectMenuFilterProps extends TextInputProps {
  value: string
  }
  @@ -345,6 +347,7 @@ declare module '@primer/components' {
  Tabs: React.FunctionComponent<SelectMenuTabsProps>
  Tab: React.FunctionComponent<SelectMenuTabProps>
  TabPanel: React.FunctionComponent<SelectMenuTabPanelProps>
  + Header: React.FunctionComponent<SelectMenuHeaderProps>
  }
  export interface SideNavProps extends CommonProps, BorderProps, Omit<React.HTMLAttributes<HTMLDivElement>, 'color'> {
  