CI: Remove deprecated GitHub Actions items

[gandro]

This issue proposes two tech-debt removal items to maintain our current GHA:

• Our GitHub actions currently still use the legacy way of defining outputs. We need to use the new way by June 2023.
• The upload artifacts action during releases fails quite often and needs manual restarts (c.f. upstream issue Repeated failures uploading binaries, curl: (55) OpenSSL SSL_write: Connection reset by peer, errno 104 skx/github-action-publish-binaries#33) - we could likely replace this action with the GH CLI and a retry loop

[tklauser]

• The upload artifacts action during releases fails quite often and needs manual restarts (c.f. upstream issue Repeated failures uploading binaries, curl: (55) OpenSSL SSL_write: Connection reset by peer, errno 104 skx/github-action-publish-binaries#33) - we could likely replace this action with the GH CLI and a retry loop

In the cilium-cli repo we recently switched to use softprops/action-gh-release to create releases and upload their artifacts: https://github.com/cilium/cilium-cli/blob/1a05658d0635ba0e817907e3488a07b988deec4b/.github/workflows/release.yaml#L26-L36 It worked great so far, namely not hitting any issues with uploading binaries.

Maybe that action would be useful for this repo as well. The PR introducing it has some more details: cilium/cilium-cli#1433 (plus the follow-up fix for the release name cilium/cilium-cli#1435)