message: docs(serverless-component): document static pages caching. Also clarify which parts of SSG are currently supported.
diff: @@ -19,6 +19,7 @@ A zero configuration Nextjs 9.0 [serverless component](https://github.com/server
  - [Lambda@Edge configuration](#lambda-at-edge-configuration)
  - [Custom domain name](#custom-domain-name)
  - [Custom CloudFront configuration](#custom-cloudfront-configuration)
  +- [Static pages caching](#static-pages-caching)
  - [Public directory caching](#public-directory-caching)
  - [AWS Permissions](#aws-permissions)
  - [Architecture](#architecture)
  @@ -56,8 +57,11 @@ With a simplified architecture and no use of CloudFormation, there are no limits
  Nextjs build assets `/_next/*` served from CloudFront.
  - [x] [User static / public folders](https://github.com/zeit/next.js#static-file-serving-eg-images).
  Any of your assets in the static or public folders are uploaded to S3 and served from CloudFront automatically.
  -- [ ] [getStaticProps / getStaticPaths / getServerSideProps](https://nextjs.org/blog/next-9-3#next-gen-static-site-generation-ssg-support).
  - Currently in progress. See [this RFC](https://github.com/danielcondemarin/serverless-next.js/issues/355) for updates.
  +- [x] Opt-in to static generation (SSG) via `getStaticProps`.
  +- [x] Opt-in to server-side rendering (SSR) via `getServerSideProps`.
  +- [x] Statically generate a set of routes from dynamic sources via `getStaticPaths`.
  +- [ ] Statically generate a set of routes from dynamic sources via `getStaticPaths` using fallback page. See [RFC](https://github.com/danielcondemarin/serverless-next.js/issues/355) for updates.
  +- [ ] Preview mode. See [RFC](https://github.com/danielcondemarin/serverless-next.js/issues/355) for updates.
  ### Getting started
  @@ -162,6 +166,17 @@ myNextApplication:
  This is particularly useful for caching any of your next.js pages at CloudFront's edge locations. See [this](https://github.com/danielcondemarin/serverless-next.js/tree/master/packages/serverless-component/examples/app-with-custom-caching-config) for an example application with custom cache configuration.
  +### Static pages caching
  +
  +Statically rendered pages (i.e. HTML pages that are uploaded to S3) have the following Cache-Control set:
  +
  +```
  +cache-control: public, max-age=0, s-maxage=2678400, must-revalidate
  +```
  +
  +`s-maxage` allows Cloudfront to cache the pages at the edge locations for 31 days.
  +`max-age=0` in combination with `must-revalidate` ensure browsers never cache the static pages. This allows Cloudfront to be in full control of caching TTLs. On every deployment an invalidation`/\*` is created to ensure users get fresh content.
  +
  ### Public directory caching
  By default, common image formats(`gif|jpe?g|jp2|tiff|png|webp|bmp|svg|ico`) under `/public` or `/static` folders
  