add synapse batch tag package-composite-v1 (#15974)

Author: Alancere

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

@@ -13,12 +13,22 @@ go:
 
 ``` yaml $(go) && $(multiapi)
 batch:
+  - tag: package-composite-v1
   - tag: package-2019-06-01-preview
   - tag: package-2020-12-01
   - tag: package-2021-03
   - tag: package-preview-2021-06
 ```
 
+### Tag: package-composite-v1 and go
+
+These settings apply only when `--tag=package-composite-v1 --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-composite-v1' && $(go)
+output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/v1.0/$(namespace)
+```
+
 ### Tag: package-2019-06-01-preview and go
 
 These settings apply only when `--tag=package-2019-06-01-preview --go` is specified on the command line.