Add hono-zod-openapi to 3rd party middlewares list (#754)

Author: paolostyle

docs/middleware/third-party.md

@@ -30,6 +30,7 @@ Most of this middleware leverages external libraries.
 - [Scalar](https://github.com/scalar/scalar/tree/main/integrations/hono)
 - [Swagger UI](https://github.com/honojs/middleware/tree/main/packages/swagger-ui)
 - [Hono OpenAPI](https://github.com/rhinobase/hono-openapi)
+- [hono-zod-openapi](https://github.com/paolostyle/hono-zod-openapi)
 
 ### Others