Pipeline submission fails when ContainerOp has numbers as command line arguments

[Ark-kun]

Root cause: In Kubernetes/Argo, the valid type of command-line arguments is string. The ContainerOp class does not convert all arguments to strings, so the compiler produces invalid Workflows.

The pipeline spec is invalid.: InvalidInputError: Invalid argo workflow format. Workflow:
...
json: cannot unmarshal number into Go struct field Container.args of type string

Interestingly, argo lint does not catch the problem. (Is that because Argo uses yaml.Unmarshal which does not validate enough?)