Release uses an unsupported action

[pmalek]

Release workflow uses an unsupported release action: actions/create-release@v1.

Because it uses the deprecated set-output command, we'll have to approach this sooner or later.

Exemplar CI failure: https://github.com/Kong/kubernetes-testing-framework/actions/runs/3628481705/jobs/6119549896#step:5:12

Proposed solution

Use an action that will not yield warnings and not be marked as unsupported, e.g. softprops/action-gh-release

Acceptance criteria

• release pipeline uses an action that is not marked as unsupported

[mflendrich]

@pmalek please add a proposed solution and AC