Update Rails version section in README

The supported Rails versions - section is now up to date and points to the correct branches for each Rails version.

README.md

@@ -52,8 +52,10 @@ or visit the existing demo at https://alchemy-demo.herokuapp.com
 
 ## 🚂 Rails Version
 
-**This version of AlchemyCMS runs with Rails 7.0, 6.1 and 6.0**
+**This version of AlchemyCMS runs with Rails 7.0**
 
+* For a Rails 6.1 compatible version use the [`7.0-stable` branch](https://github.com/AlchemyCMS/alchemy_cms/tree/7.0-stable).
+* For a Rails 6.0 compatible version use the [`6.1-stable` branch](https://github.com/AlchemyCMS/alchemy_cms/tree/6.1-stable).
 * For a Rails 5.2 compatible version use the [`5.3-stable` branch](https://github.com/AlchemyCMS/alchemy_cms/tree/5.3-stable).
 * For a Rails 5.0 or 5.1 compatible version use the [`4.5-stable` branch](https://github.com/AlchemyCMS/alchemy_cms/tree/4.5-stable).
 * For a Rails 4.2 compatible version use the [`3.6-stable` branch](https://github.com/AlchemyCMS/alchemy_cms/tree/3.6-stable).