fix(docs): container-set-template workflow example

[sxllwx]

no such file or directory appears when run the container-set-template in the example.

Signed-off-by: scott scottwangsxll@gmail.com

Fixes:

When I tried to run the container-set-template- workflow in the sample, I encountered the following error (and it can be reproduced).

Name:                container-set-template-qkrbz
Namespace:           argo
ServiceAccount:      unset (will run with the default ServiceAccount)
Status:              Error
Message:             Error (exit code 1): open /mainctrfs/workspace/message: no such file or directory
Conditions:
 PodRunning          False
 Completed           True
Created:             Thu Feb 02 17:59:42 +0800 (3 hours ago)
Started:             Thu Feb 02 17:59:42 +0800 (3 hours ago)
Finished:            Thu Feb 02 17:59:54 +0800 (3 hours ago)
Duration:            12 seconds
Progress:            3/4
ResourcesDuration:   10s*(100Mi memory),10s*(1 cpu)

STEP                             TEMPLATE  PODNAME                       DURATION  MESSAGE
 ⚠ container-set-template-qkrbz  main      container-set-template-qkrbz  9s        Error (exit code 1): open /mainctrfs/workspace/message: no such file or directory

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