Fix workspace not getting copied with --last

[piyush-garg]

This will fix the issue of workspace not getting copied on
using pipeline. task and clustertask start with --last

Fix #638

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Release Notes

Fix workspace not getting copied with --last on start

[tekton-robot]

The following is the coverage report on pkg/.
Say /test pull-tekton-cli-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/cmd/task/start.go	91.3%	91.4%	0.1

[chmouel]

/lgtm

Looking Good! 🤙🏽

[vdemeester]

/lgtm

[tekton-robot]

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