docs: add menu to list of components (#859)

README.md

@@ -29,6 +29,7 @@ Component | Spec | MDC Web
 [List](./packages/list) | [List Design Page](https://material.io/design/components/lists.html) | [MDC List](https://github.com/material-components/material-components-web/tree/latest-release/packages/mdc-list)
 [Material Icon](./packages/material-icon) | [Material Icon Design Page](https://material.io/design/iconography/system-icons.html#design-principles) | [Material Icon Tool](https://material.io/tools/icons/?style=baseline)
 [Menu Surface](./packages/menu-surface) | [Menu Surface Design Page](https://material.io/design/components/menus.html#design-principles) | [MDC Menu Surface](https://github.com/material-components/material-components-web/tree/master/packages/mdc-menu-surface)
+[Menu](./packages/menu) | [Menu Design Page](https://material.io/design/components/menus.html#design-principles) | [MDC Menu](https://github.com/material-components/material-components-web/tree/master/packages/mdc-menu)
 [Notched Outline](./packages/notched-outline) | [Text Field Design Page](https://material.io/design/components/text-fields.html) | [MDC Notched Outline](https://github.com/material-components/material-components-web/tree/master/packages/mdc-notched-outline)
 [Radio](./packages/radio) | [Radio Design Page](https://material.io/design/components/selection-controls.html#radio-buttons) | [MDC Radio](https://github.com/material-components/material-components-web/tree/master/packages/mdc-radio)
 [Ripple](./packages/ripple) | [Ripple Design Page](https://material.io/design/interaction/states.html) | [MDC Ripple](https://github.com/material-components/material-components-web/tree/master/packages/mdc-ripple)