Updates readme

Author: FumingZhang

specification/containerservice/resource-manager/readme.md

@@ -34,10 +34,18 @@ These are the global settings for the ContainerServices API.
 
 ``` yaml
 openapi-type: arm
-tag: package-2021-05
+tag: package-2021-07
 ```
 
 
+### Tag: package-2021-07
+
+These settings apply only when `--tag=package-2021-07` is specified on the command line.
+
+```yaml $(tag) == 'package-2021-07'
+input-file:
+  - Microsoft.ContainerService/stable/2021-07-01/managedClusters.json
+```
 ### Tag: package-2021-05
 
 These settings apply only when `--tag=package-2021-05` is specified on the command line.
@@ -46,6 +54,7 @@ These settings apply only when `--tag=package-2021-05` is specified on the comma
 input-file:
   - Microsoft.ContainerService/stable/2021-05-01/managedClusters.json
 ```
+
 ### Tag: package-2021-03
 
 These settings apply only when `--tag=package-2021-03` is specified on the command line.
@@ -708,5 +717,3 @@ directive:
     from: containerService.json
     reason: ACS service is deprecated so a PATCH endpoint won't be implemented
 ```
-
-