Update roadmap for `Signing of release artifacts`
Update roadmap for `Signing of release artifacts`

We should remove the link to the previous issue because the work is now
being tracked in the enhancement.

Beside this, we update the outcome to reflect the current state.

Signed-off-by: Sascha Grunert <70ab469ddb2ac3e35f32ed7c2fd1cca514b2e879@redhat.com>

kubernetes/sig-release