chore: update gapic-generator-java to 0.0.20 (#188)

This PR was generated using Autosynth. 🌈

Synth log will be available here:
https://source.cloud.google.com/results/invocations/ca0c8ac8-6f14-468f-80f2-67e8a2c09f54/targets

- [ ] To automatically regenerate this PR, check this box.

PiperOrigin-RevId: 357800868
Source-Link: googleapis/googleapis@e8bc447

Author: yoshi-automation

java-workflows/google-cloud-workflows/src/main/java/com/google/cloud/workflows/v1beta/stub/GrpcWorkflowsStub.java

@@ -270,41 +270,50 @@ public GrpcOperationsStub getOperationsStub() {
     return operationsStub;
   }
 
+  @Override
   public UnaryCallable<ListWorkflowsRequest, ListWorkflowsResponse> listWorkflowsCallable() {
     return listWorkflowsCallable;
   }
 
+  @Override
   public UnaryCallable<ListWorkflowsRequest, ListWorkflowsPagedResponse>
       listWorkflowsPagedCallable() {
     return listWorkflowsPagedCallable;
   }
 
+  @Override
   public UnaryCallable<GetWorkflowRequest, Workflow> getWorkflowCallable() {
     return getWorkflowCallable;
   }
 
+  @Override
   public UnaryCallable<CreateWorkflowRequest, Operation> createWorkflowCallable() {
     return createWorkflowCallable;
   }
 
+  @Override
   public OperationCallable<CreateWorkflowRequest, Workflow, OperationMetadata>
       createWorkflowOperationCallable() {
     return createWorkflowOperationCallable;
   }
 
+  @Override
   public UnaryCallable<DeleteWorkflowRequest, Operation> deleteWorkflowCallable() {
     return deleteWorkflowCallable;
   }
 
+  @Override
   public OperationCallable<DeleteWorkflowRequest, Empty, OperationMetadata>
       deleteWorkflowOperationCallable() {
     return deleteWorkflowOperationCallable;
   }
 
+  @Override
   public UnaryCallable<UpdateWorkflowRequest, Operation> updateWorkflowCallable() {
     return updateWorkflowCallable;
   }
 
+  @Override
   public OperationCallable<UpdateWorkflowRequest, Workflow, OperationMetadata>
       updateWorkflowOperationCallable() {
     return updateWorkflowOperationCallable;

java-workflows/google-cloud-workflows/src/test/java/com/google/cloud/workflows/v1beta/MockWorkflowsImpl.java

@@ -70,7 +70,13 @@ public void listWorkflows(
     } else if (response instanceof Exception) {
       responseObserver.onError(((Exception) response));
     } else {
-      responseObserver.onError(new IllegalArgumentException("Unrecognized response type"));
+      responseObserver.onError(
+          new IllegalArgumentException(
+              String.format(
+                  "Unrecognized response type %s for method ListWorkflows, expected %s or %s",
+                  response.getClass().getName(),
+                  ListWorkflowsResponse.class.getName(),
+                  Exception.class.getName())));
     }
   }
 
@@ -84,7 +90,13 @@ public void getWorkflow(GetWorkflowRequest request, StreamObserver<Workflow> res
     } else if (response instanceof Exception) {
       responseObserver.onError(((Exception) response));
     } else {
-      responseObserver.onError(new IllegalArgumentException("Unrecognized response type"));
+      responseObserver.onError(
+          new IllegalArgumentException(
+              String.format(
+                  "Unrecognized response type %s for method GetWorkflow, expected %s or %s",
+                  response.getClass().getName(),
+                  Workflow.class.getName(),
+                  Exception.class.getName())));
     }
   }
 
@@ -99,7 +111,13 @@ public void createWorkflow(
     } else if (response instanceof Exception) {
       responseObserver.onError(((Exception) response));
     } else {
-      responseObserver.onError(new IllegalArgumentException("Unrecognized response type"));
+      responseObserver.onError(
+          new IllegalArgumentException(
+              String.format(
+                  "Unrecognized response type %s for method CreateWorkflow, expected %s or %s",
+                  response.getClass().getName(),
+                  Operation.class.getName(),
+                  Exception.class.getName())));
     }
   }
 
@@ -114,7 +132,13 @@ public void deleteWorkflow(
     } else if (response instanceof Exception) {
       responseObserver.onError(((Exception) response));
     } else {
-      responseObserver.onError(new IllegalArgumentException("Unrecognized response type"));
+      responseObserver.onError(
+          new IllegalArgumentException(
+              String.format(
+                  "Unrecognized response type %s for method DeleteWorkflow, expected %s or %s",
+                  response.getClass().getName(),
+                  Operation.class.getName(),
+                  Exception.class.getName())));
     }
   }
 
@@ -129,7 +153,13 @@ public void updateWorkflow(
     } else if (response instanceof Exception) {
       responseObserver.onError(((Exception) response));
     } else {
-      responseObserver.onError(new IllegalArgumentException("Unrecognized response type"));
+      responseObserver.onError(
+          new IllegalArgumentException(
+              String.format(
+                  "Unrecognized response type %s for method UpdateWorkflow, expected %s or %s",
+                  response.getClass().getName(),
+                  Operation.class.getName(),
+                  Exception.class.getName())));
     }
   }
 }

java-workflows/synth.metadata

@@ -4,15 +4,15 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-workflows.git",
-        "sha": "592501d6150886bf9531e669733f4dd3ed7f5fa8"
+        "sha": "286279b88b160d30bff14772681a57fbccb5f43d"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "8d8c008e56f1af31d57f75561e0f1848ffb29eeb",
-        "internalRef": "356341083"
+        "sha": "e8bc4471a88ac5f60defe3ed436f517174e59ba0",
+        "internalRef": "357800868"
       }
     },
     {