commands: filter noisy fsverity support warning

containerd v2 (vendored via buildkit v0.32.0-rc1) now logs a warning
when opening a local content store on a filesystem without fsverity
support, which it probes by trying to enable verity on a temp file.
This fails on overlayfs, tmpfs, and similar filesystems common in
container and CI environments, so every imagetools oci-layout inspect
or create emitted an alarming but non-actionable warning.

Add the message to the existing logutil filter (extended to Warn level)
so it is kept out of user output, matching how other containerd/buildkit
log noise is already suppressed.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

commands/root.go

@@ -91,10 +91,16 @@ func NewRootCmd(name string, isPlugin bool, dockerCli *command.DockerCli) *cobra
 
 	logrus.AddHook(logutil.NewFilter([]logrus.Level{
 		logrus.DebugLevel,
+		logrus.WarnLevel,
 	},
 		"serving grpc connection",
 		"stopping session",
 		"using default config store",
+		// containerd's local content store probes fsverity support by trying to
+		// enable it on a temp file, which fails on filesystems without fsverity
+		// (overlayfs, tmpfs, etc.) and logs a warning. This is expected and not
+		// actionable for oci-layout operations, so keep it out of user output.
+		"failed check for fsverity support",
 	))
 
 	addCommands(cmd, &opt, dockerCli)