package/containerd: security bump to version 1.5.18
Fixes the following security issues:
- CVE-2023-25153: Fix OCI image importer memory exhaustion
https://github.com/containerd/containerd/security/advisories/GHSA-259w-8hf6-59c2
- CVE-2023-25173: Fix supplementary groups not being set up properly
https://github.com/containerd/containerd/security/advisories/GHSA-hmfx-3pcx-653p
https://github.com/containerd/containerd/releases/tag/v1.5.18
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>