Add eventlistener list

[piyush-garg]

This will add the feature to list
eventlisteners.

Add docs and tests

Fix #530

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you
review them:

• Includes tests (if functionality changed/added)
• Includes docs (if user facing)
• Regenerate the manpages and docs with make docs and make man if needed.
• Run the code checkers with make check
• Commit messages follow commit message best practices

See the contribution guide
for more details.

Release Notes

Add eventlistener list

[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/eventlistener/eventlistener.go	Do not exist	100.0%
pkg/cmd/eventlistener/list.go	Do not exist	85.7%

[pradeepitm12]

/lgtm

[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/eventlistener/eventlistener.go	Do not exist	100.0%
pkg/cmd/eventlistener/list.go	Do not exist	85.7%

[vdemeester]

/lgtm

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: pradeepitm12, vdemeester

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [vdemeester]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment