update 1.5 Readme with new v2 version 2.2.9

Author: frantuma

README.md

@@ -33,7 +33,8 @@ The OpenAPI Specification has undergone several revisions since initial creation
 
 Swagger core Version      | Release Date | OpenAPI Spec compatibility | Notes | Status
 ------------------------- | ------------ | -------------------------- | ----- | ----
-2.2.8 (**current stable**)| 2023-01-06   | 3.x           | [tag v2.2.8](https://github.com/swagger-api/swagger-core/tree/v2.2.8) | Supported
+2.2.9 (**current stable**)| 2023-03-20   | 3.x           | [tag v2.2.9](https://github.com/swagger-api/swagger-core/tree/v2.2.9) | Supported
+2.2.8                     | 2023-01-06   | 3.x           | [tag v2.2.8](https://github.com/swagger-api/swagger-core/tree/v2.2.8) | Supported
 2.2.7                     | 2022-11-15   | 3.0           | [tag v2.2.7](https://github.com/swagger-api/swagger-core/tree/v2.2.7) | Supported
 2.2.6                     | 2022-11-02   | 3.0           | [tag v2.2.6](https://github.com/swagger-api/swagger-core/tree/v2.2.6) | Supported
 2.2.5                     | 2022-11-02   | 3.0           | [tag v2.2.5](https://github.com/swagger-api/swagger-core/tree/v2.2.5) | Supported