chore: update & simplify supported releases.

Author: rektide

README.md

@@ -92,8 +92,6 @@ Restify aims to support the Node.js LTS (Active and Maintenance) versions along
 | 18.x | **Yes**  | Restify v10.x required. |
 | 16.x | **Yes** | |
 | 14.x | **Yes** | |
-| 12.x | **No**  | Use restify v8.x, team will backport critical issues only |
-| 10.x | **No**  | Use restify v8.x, team will backport critical issues only |
 
 ## License