adding error to wf-exec-finished proto (#295)

* Add error field to WorkflowExecutionFinished proto

  Add string error = 6 to WorkflowExecutionFinished message, matching
  the existing pattern from CapabilityExecutionFinished. Regenerated
  Go bindings.

* bot: regenerate protobuf files

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Co-authored-by: De Clercq Wentzel <10665586+wentzeld@users.noreply.github.com>
Co-authored-by: app-token-issuer-engops[bot] <144731339+app-token-issuer-engops[bot]@users.noreply.github.com>

Author: 3 people

workflows/go/v2/workflow_execution_finished.pb.go

@@ -15,4 +15,5 @@ message WorkflowExecutionFinished {
   string timestamp = 4;
 
   ExecutionStatus status = 5;
+  string error = 6;
 }