Chore: export inputItem and outputItem

[chivalryq]

Signed-off-by: Qiaozp qiaozhongpei.qzp@alibaba-inc.com

Description of your changes

Export inputItem and outputItem for iterating the StepInputs/Outputs array.

Fixes #

I have:

• Read and followed KubeVela's contribution process.
• Related Docs updated properly. In a new feature or configuration option, an update to the documentation is necessary.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

Special notes for your reviewer

[FogDong]

Please meet the lint check.

[codecov]

Codecov Report

Base: 65.13% // Head: 67.49% // Increases project coverage by +2.36% 🎉

Coverage data is based on head (d1a466e) compared to base (e8f00ce).
Patch coverage: 33.33% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #125      +/-   ##
==========================================
+ Coverage   65.13%   67.49%   +2.36%     
==========================================
  Files          41       49       +8     
  Lines        4228     4323      +95     
==========================================
+ Hits         2754     2918     +164     
+ Misses       1108     1036      -72     
- Partials      366      369       +3     

Flag	Coverage Δ
e2etests	24.42% <0.00%> (?)
unit-test	65.13% <33.33%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
api/v1alpha1/types.go	0.00% <ø> (ø)
pkg/executor/workflow.go	79.59% <33.33%> (+0.67%)	⬆️
api/v1alpha1/register.go	100.00% <0.00%> (ø)
pkg/features/controller_features.go	100.00% <0.00%> (ø)
pkg/webhook/register.go	100.00% <0.00%> (ø)
pkg/monitor/metrics/workflow.go	0.00% <0.00%> (ø)
version/version.go	0.00% <0.00%> (ø)
pkg/monitor/watcher/workflow.go	96.15% <0.00%> (ø)
pkg/types/types.go	33.33% <0.00%> (ø)
... and 15 more

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[chivalryq]

ping @FogDong