Cannot create WorkflowTemplate with unsupplied inputs

[simster7]

What happened:

I tried to create a set of WorkflowTemplates from the examples and received an error:

$ argo template create examples/workflow-template/templates.yaml
2020/04/27 10:26:18 Failed to create workflow template: templates.whalesay-template inputs.parameters.message was not supplied

What you expected to happen:

I expected to be able to create these templates without an error.

How to reproduce it (as minimally and precisely as possible):

Run argo template create examples/workflow-template/templates.yaml

Anything else we need to know?:

This is the offending commit: #2644

[simster7]

Fixed in #2869