Update buildah to v1.11.0

Vendor in the latest changes for buildah to apply the implemented
features here as well.

Signed-off-by: Sascha Grunert <sgrunert@suse.com>

vendor/github.com/containers/buildah/pkg/cgroups/cgroups_supported.go

@@ -0,0 +1,31 @@
+// +build linux
+
+package cgroups
+
+import (
+	"sync"
+	"syscall"
+)
+
+const (
+	_cgroup2SuperMagic = 0x63677270
+)
+
+var (
+	isUnifiedOnce sync.Once
+	isUnified     bool
+	isUnifiedErr  error
+)
+
+// IsCgroup2UnifiedMode returns whether we are running in cgroup 2 cgroup2 mode.
+func IsCgroup2UnifiedMode() (bool, error) {
+	isUnifiedOnce.Do(func() {
+		var st syscall.Statfs_t
+		if err := syscall.Statfs("/sys/fs/cgroup", &st); err != nil {
+			isUnified, isUnifiedErr = false, err
+		} else {
+			isUnified, isUnifiedErr = st.Type == _cgroup2SuperMagic, nil
+		}
+	})
+	return isUnified, isUnifiedErr
+}

vendor/github.com/containers/buildah/pkg/cgroups/cgroups_unsupported.go

@@ -0,0 +1,8 @@
+// +build !linux
+
+package cgroups
+
+// IsCgroup2UnifiedMode returns whether we are running in cgroup 2 cgroup2 mode.
+func IsCgroup2UnifiedMode() (bool, error) {
+	return false, nil
+}