fix: Add async context manager return types (#378)

* fix: Add async context manager return types

chore: Mock return_value should not populate oneof message fields

chore: Support snippet generation for services that only support REST transport

chore: Update gapic-generator-python to v1.11.0
PiperOrigin-RevId: 545430278

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Source-Link: googleapis/googleapis-gen@b3f18d0
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packages/google-cloud-containeranalysis/google/cloud/devtools/containeranalysis_v1/services/container_analysis/async_client.py

@@ -828,7 +828,7 @@ async def sample_get_vulnerability_occurrences_summary():
         # Done; return the response.
         return response
 
-    async def __aenter__(self):
+    async def __aenter__(self) -> "ContainerAnalysisAsyncClient":
         return self
 
     async def __aexit__(self, exc_type, exc, tb):

packages/google-cloud-containeranalysis/samples/generated_samples/snippet_metadata_google.devtools.containeranalysis.v1.json

@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-containeranalysis",
-    "version": "2.12.1"
+    "version": "0.1.0"
   },
   "snippets": [
     {