docs(readme): update plugin version syntax (#862)

Author: Fdawgs

README.md

@@ -26,12 +26,11 @@ npm i @fastify/swagger
 
 | Plugin version | Fastify version |
 | -------------- | --------------- |
-| `^9.x`         | `^5.x`          |
-| `^8.x`         | `^4.x`          |
-| `^7.x`         | `^4.x`          |
+| `>=9.x`        | `^5.x`          |
+| `>=7.x <9.x`   | `^4.x`          |
 | `^6.x`         | `^3.x`          |
-| `^3.x`         | `^2.x`          |
-| `^1.x`         | `^1.x`          |
+| `>=3.x <6.x`   | `^2.x`          |
+| `>=1.x <3.x`   | `^1.x`          |
 
 
 Please note that if a Fastify version is out of support, then so are the corresponding versions of this plugin