skip showcase for now which requires showcase_mode

Author: chingor13

generation_config.yaml

@@ -3014,15 +3014,6 @@ libraries:
   GAPICs:
   - proto_path: google/cloud/workstations/v1
   - proto_path: google/cloud/workstations/v1beta
-- api_shortname: showcase
-  excluded_poms: gapic-showcase-bom
-  name_pretty: Showcase
-  api_description: Showcase module
-  product_documentation: https://cloud.google.com/dummy
-  distribution_name: com.google.cloud:gapic-showcase
-  library_type: OTHER
-  GAPICs:
-  - proto_path: schema/google/showcase/v1beta1
 - api_shortname: common-protos
   name_pretty: Common Protos
   product_documentation: https://github.com/googleapis/api-common-protos