chore: enable generation for google-cloud-container (#16722)

Author: jskeet

librarian.yaml

@@ -1478,7 +1478,6 @@ libraries:
       - tests/system
       - tests/system/__init__.py
       - tests/system/smoke_test.py
-    skip_generate: true
     python:
       opt_args_by_api:
         google/container/v1:

packages/google-cloud-container/.repo-metadata.json

@@ -1,17 +1,16 @@
 {
-  "api_description": "The Google Kubernetes Engine API is used for building and managing container based applications, powered by the open source Kubernetes technology.",
-  "api_id": "container.googleapis.com",
-  "api_shortname": "container",
-  "client_documentation": "https://cloud.google.com/python/docs/reference/container/latest",
-  "default_version": "v1",
-  "distribution_name": "google-cloud-container",
-  "issue_tracker": "https://issuetracker.google.com/savedsearches/559746",
-  "language": "python",
-  "library_type": "GAPIC_AUTO",
-  "name": "container",
-  "name_pretty": "Kubernetes Engine",
-  "product_documentation": "https://cloud.google.com/kubernetes-engine/",
-  "release_level": "stable",
-  "repo": "googleapis/google-cloud-python",
-  "requires_billing": true
+    "api_description": "The Google Kubernetes Engine API is used for building and managing container based applications, powered by the open source Kubernetes technology.",
+    "api_id": "container.googleapis.com",
+    "api_shortname": "container",
+    "client_documentation": "https://cloud.google.com/python/docs/reference/container/latest",
+    "default_version": "v1",
+    "distribution_name": "google-cloud-container",
+    "issue_tracker": "https://issuetracker.google.com/savedsearches/559746",
+    "language": "python",
+    "library_type": "GAPIC_AUTO",
+    "name": "container",
+    "name_pretty": "Kubernetes Engine",
+    "product_documentation": "https://cloud.google.com/kubernetes-engine/",
+    "release_level": "stable",
+    "repo": "googleapis/google-cloud-python"
 }

packages/google-cloud-container/noxfile.py

@@ -390,7 +390,6 @@ def docs(session):
     shutil.rmtree(os.path.join("docs", "_build"), ignore_errors=True)
     session.run(
         "sphinx-build",
-        "-W",  # warnings as errors
         "-T",  # show full traceback on exception
         "-N",  # no colors
         "-b",