Update README.md

Author: stylewarning

README.md

@@ -4,5 +4,8 @@ This repository contains base images for the [Coalton](https://github.com/coalto
 
 The following implementations are supported:
 - [SBCL](./sbcl)
-- [Allegro CL](./allegro)
 - [Clozure CL](./ccl)
+
+The following implementations have been disabled due to license expiration:
+
+- [Allegro CL](./allegro)