Revert "generate go sdk for authorization (Azure#11942)" (Azure#11944)

This reverts commit c00cdbf.

Author: ArcturusZhang

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

@@ -18,7 +18,6 @@ batch:
   - tag: package-2018-01-01-preview
   - tag: package-2018-07-01-preview
   - tag: package-2018-09-01-preview
-  - tag: package-2020-04-preview
 ```
 
 ### Tag: package-2015-07-01 and go
@@ -65,12 +64,3 @@ Please also specify `--go-sdk-folder=<path to the root directory of your azure-s
 ``` yaml $(tag) == 'package-2018-09-01-preview' && $(go)
 output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/2018-09-01-preview/$(namespace)
 ```
-
-### Tag: package-2020-04-preview and go
-
-These settings apply only when `--tag=package-2020-04-preview --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-2020-04-preview' && $(go)
-output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/2020-04-01-preview/$(namespace)
-```