message: Made href optional on Link types.
diff: @@ -211,7 +211,7 @@ declare module '@primer/components' {
  export const Label: React.FunctionComponent<LabelProps>
  export interface LinkProps extends CommonProps, TypographyProps {
  - href: string
  + href?: string
  underline?: boolean
  }
  @@ -242,7 +242,7 @@ declare module '@primer/components' {
  }
  export interface TabNavLinkProps extends CommonProps {
  - href: string
  + href?: string
  selected?: boolean
  }
  @@ -286,7 +286,7 @@ declare module '@primer/components' {
  }
  export interface UnderlineNavLinkProps extends CommonProps {
  - href: string
  + href?: string
  selected?: boolean
  }
  