bug: `cytopia/upload-artifact-verify-action` is unmaintained, using deprecated actions

[embik]

Describe the bug

Our latest goreleaser job failed: https://github.com/kcp-dev/kcp/actions/runs/13503608621/job/37727922287

Error: This request has been automatically failed because it uses a deprecated version of actions/download-artifact: v3. Learn more: https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/.
This request has been automatically failed because it uses a deprecated version of actions/upload-artifact: v3. Learn more: https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/

The action, https://github.com/cytopia/upload-artifact-verify-action, looks unmaintained, we should remove it from our actions and use the upload/download actions directly before cutting v0.27.0.

Steps To Reproduce

N/A

Expected Behaviour

gorelease action works.

Additional Context

No response