Added tag for 2024-09-01-preview in readme file

Author: saprakas

specification/containerinstance/resource-manager/readme.md

@@ -26,7 +26,16 @@ These are the global settings for the ContainerInstance API.
 
 ``` yaml
 openapi-type: arm
-tag: package-preview-2024-05
+tag: package-preview-2024-09
+```
+
+### Tag: package-preview-2024-09
+
+These settings apply only when `--tag=package-preview-2024-09` is specified on the command line.
+
+```yaml $(tag) == 'package-preview-2024-09'
+input-file:
+  - Microsoft.ContainerInstance/preview/2024-09-01-preview/containerInstance.json
 ```
 
 ### Tag: package-preview-2024-05