Add tkn approvaltask describe command

[PuneetPunamiya]

• ApprovalTask Describe Command UX

╰─ ./tkn-approvaltask describe test-6mml7-wait       
📦 Name:              test-6mml7-wait
🗂  Namespace:        default
🏷️  PipelineRunRef:   test-6mml7 

👥 Approvers
   * foo
   * bar
   * kubernetes-admin

👨‍💻 ApproverResponse

Name   ApproverResponse   Message
foo    ✅                  ---

🌡️  Status

NumberOfApprovalsRequired   PendingApprovals   STATUS
2                           1                  Pending

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: PuneetPunamiya

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• OWNERS [PuneetPunamiya]

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[piyush-garg]

/lgtm