v1.0.0-rc1

First release candidate: the runtz scanner CLI (sca, sast, pkgscan, k8s
scanners, CI/CD severity gate, self-updater).

Publishing this release triggers release.yml: GoReleaser builds and
attaches the linux/darwin amd64/arm64 binaries to this release, and
runtzdev/runtz-cli is pushed to Docker Hub.