docs(README): update install instructions

Author: notrab

gatsby-source-graphcms/README.md

@@ -24,14 +24,12 @@
 
 ## Installation
 
-> Note: Gatsby v4 requires Node.js >= 14.15.
-
-To install the next version of this plugin, make sure to use the `@next` tag when installing:
-
 ```shell
-yarn add gatsby-source-graphcms@next gatsby-plugin-image@next
+yarn add gatsby-source-graphcms gatsby-plugin-image
 ```
 
+> Note: Gatsby v4 requires Node.js >= 14.15.
+
 ## Configuration
 
 > We recommend using environment variables with your GraphCMS `token` and `endpoint` values. You can learn more about using environment variables with Gatsby [here](https://www.gatsbyjs.org/docs/environment-variables).