storagecache add batch tag (Azure#16313)

Author: Alancere

specification/storagecache/resource-manager/readme.go.md

@@ -13,6 +13,7 @@ go:
 
 ``` yaml $(go) && $(multiapi)
 batch:
+  - tag: package-2021-09
   - tag: package-2021-05
   - tag: package-2021-03
   - tag: package-2020-10-01
@@ -21,6 +22,15 @@ batch:
   - tag: package-2019-08
 ```
 
+### Tag: package-2021-09 and go
+
+These settings apply only when `--tag=package-2021-09 --go` is specified on the command line.
+Please also specify `--go-sdk-folder=<path to the root directory of your azure-sdk-for-go clone>`.
+
+``` yaml $(tag) == 'package-2021-09' && $(go)
+output-folder: $(go-sdk-folder)/services/$(namespace)/mgmt/2021-09-01/$(namespace)
+```
+
 ### Tag: package-2021-05 and go
 
 These settings apply only when `--tag=package-2021-05 --go` is specified on the command line.