support from in finally tasks

[pritidesai]

Similar to tasks, finally tasks can have PipelineResources as inputs and outputs for in the Pipeline.

The only difference here is, final tasks with an input resource can not have a from clause
like a PipelineTask from tasks section. For example:

spec:
  tasks:
    - name: tests
      taskRef:
        Name: integration-test
      resources:
        inputs:
          - name: source
            resource: tektoncd-pipeline-repo
        outputs:
          - name: workspace
            resource: my-repo
  finally:
    - name: clear-workspace
      taskRef:
        Name: clear-workspace
      resources:
        inputs:
          - name: workspace
            resource: my-repo
            from: #invalid
              - tests

Design and implement how can we specify from clause in finally tasks.

References:

finally Design Doc
finally type PR
finally functionality PR

[pritidesai]

/kind feature

[tekton-robot]

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[tekton-robot]

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[tekton-robot]

@tekton-robot: Closing this issue.

In response to this:

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

/close

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[bobcatfish]

I'm not sure this is worth doing until we resolve #1673 anyway