chore: update readme for GA (#239)

* chore: update readme for GA

* Apply suggestions from code review

Co-authored-by: Kyle Rollins <kyleblankrollins@gmail.com>

Co-authored-by: Kyle Rollins <kyleblankrollins@gmail.com>
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: 3 people

README.md

@@ -1,13 +1,10 @@
 ![Netlify Build plugin Gatsby – Run Gatsby seamlessly on Netlify](netlify-gatsby-plugin.png)
 
-# Essential Gatsby Plugin - v2 beta
+# Essential Gatsby Plugin - v2
 
-This version of the Essential Gatsby build plugin is a beta release, supporting
-the new features of Gatsby 4 including the SSR and DSG
-[render modes](https://v4.gatsbyjs.com/docs/conceptual/rendering-options/). For
-older versions of Gatsby, please use
-[version 1.x of the build plugin](https://github.com/netlify/netlify-plugin-gatsby/tree/v1),
-which is installed automatically for new Gatsby sites.
+The Essential Gatsby build plugin enables caching of builds, SSR and DSG
+[render modes](https://v4.gatsbyjs.com/docs/conceptual/rendering-options/) and
+Gatsby Functions. It is installed automatically for all new Gatsby sites.
 
 > **Note:**
 >
@@ -20,58 +17,40 @@ which is installed automatically for new Gatsby sites.
 > - Essential Gatsby is not compatible with the Gatsby community plugin
 >   [gatsby-plugin-netlify-cache](https://www.gatsbyjs.com/plugins/gatsby-plugin-netlify-cache/).
 
-## Installation and Configuration
+## Installation
 
-<!-- All sites deployed to Netlify with Gatsby will automatically install this plugin
-for a seamless experience.
+Gatsby sites need two plugins to support all features.
 
-This means that you don't have to do anything — just build and deploy your site
-to Netlify as usual and we'll handle the rest.
+1. The Netlify build plugin, called "Essential Gatsby" or
+   `@netlify/plugin-gatsby`. This is installed automatically for all Gatsby
+   sites deployed to Netlify.
+2. The Gatsby plugin `gatsby-plugin-netlify`. This needs to be manually
+   installed.
 
-You're able to
-[remove the plugin](https://docs.netlify.com/configure-builds/build-plugins/#remove-a-plugin)
-at any time by visiting the **Plugins** tab for your site in the Netlify UI. -->
+### Installing the Netlify build plugin
 
-There are three steps to enable support for Gatsby 4 in your Netlify site. This
-includes installing _two_ plugins: a Netlify build plugin called "Essential
-Gatsby Plugin", and a Gatsby plugin called "gatsby-plugin-netlify":
+New Gatsby sites on Netlify automatically install the Essential Gatsby build plugin. You can confirm this in the build logs. If you need to install it
+manually, you have two options:
 
-- [Install version 2 beta of `@netlify/plugin-gatsby`](#install-the-netlify-build-plugin)
-  (the Netlify build plugin)
-- [Install version 4 beta of `gatsby-plugin-netlify`](#install-the-gatsby-plugin)
-  (the Gatsby plugin)
+- [The Netlify UI](https://docs.netlify.com/configure-builds/build-plugins/#ui-installation). Here, you can search for "Essential Gatsby" and install the plugin.
 
-### Install the Netlify build plugin
+- [File-based plugin installation](https://docs.netlify.com/configure-builds/build-plugins/#file-based-installation). You can install the plugin as `@netlify/plugin-gatsby` in your `netlify.toml` file.
+   
 
-1. Create a `netlify.toml` in the root of your project. Your file should include
-   the plugins section below:
+### Install the Gatsby Plugin
 
-```toml
-[[plugins]]
-package = "@netlify/plugin-gatsby"
-```
+You should also install the Gatsby plugin
+[gatsby-plugin-netlify](https://www.gatsbyjs.org/plugins/gatsby-plugin-netlify/).
+This is required for SSR pages, and adds support for Gatsby redirects and asset
+caching rules:
 
-2. From your project's base directory, add this plugin to `devDependencies` in
-   `package.json`.
+1. Add the package as a dependency:
 
 ```shell
-npm install -D @netlify/plugin-gatsby@^2.0.0-beta
+npm install -D gatsby-plugin-netlify
 ```
 
-Read more about
-[file-based plugin installation](https://docs.netlify.com/configure-builds/build-plugins/#file-based-installation)
-in our docs.
-
-## Install the Gatsby Plugin
-
-To use SSR pages you must install the beta version of
-[gatsby-plugin-netlify](https://www.gatsbyjs.org/plugins/gatsby-plugin-netlify/):
-
-```shell
-npm install -D gatsby-plugin-netlify@next
-```
-
-Then add the following to your `gatsby-config.js` file:
+2. Then add the following to your `gatsby-config.js` file:
 
 ```js
 module.exports = {
@@ -103,10 +82,6 @@ DSG pages. The best workaround is to use an image CDN such as
 or [imgix](https://github.com/imgix/gatsby) to host your images. This will give
 you faster builds and rendering too.
 
-### Beta feedback
-
-TODO: forums link
-
 ### Local development
 
 When developing Gatsby Functions it is usually easier to use the built-in