Update vendor of Buildah and imagebuilder

Fixes the testing issues we are hitting.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

vendor/github.com/containers/buildah/pkg/parse/parse.go

@@ -9,6 +9,7 @@ import (
 	"github.com/spf13/cobra"
 	"net"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -319,7 +320,7 @@ func getDockerAuth(creds string) (*types.DockerAuthConfig, error) {
 }
 
 // IDMappingOptions parses the build options related to user namespaces and ID mapping.
-func IDMappingOptions(c *cobra.Command) (usernsOptions buildah.NamespaceOptions, idmapOptions *buildah.IDMappingOptions, err error) {
+func IDMappingOptions(c *cobra.Command, isolation buildah.Isolation) (usernsOptions buildah.NamespaceOptions, idmapOptions *buildah.IDMappingOptions, err error) {
 	user := c.Flag("userns-uid-map-user").Value.String()
 	group := c.Flag("userns-gid-map-group").Value.String()
 	// If only the user or group was specified, use the same value for the
@@ -391,11 +392,26 @@ func IDMappingOptions(c *cobra.Command) (usernsOptions buildah.NamespaceOptions,
 	if len(gidmap) == 0 && len(uidmap) != 0 {
 		gidmap = uidmap
 	}
+
+	useSlirp4netns := false
+
+	if isolation == buildah.IsolationOCIRootless {
+		_, err := exec.LookPath("slirp4netns")
+		if execerr, ok := err.(*exec.Error); ok && !strings.Contains(execerr.Error(), "not found") {
+			return nil, nil, errors.Wrapf(err, "cannot lookup slirp4netns %v", execerr)
+		}
+		if err == nil {
+			useSlirp4netns = true
+		} else {
+			logrus.Warningf("could not find slirp4netns. Using host network namespace")
+		}
+	}
+
 	// By default, having mappings configured means we use a user
 	// namespace.  Otherwise, we don't.
 	usernsOption := buildah.NamespaceOption{
 		Name: string(specs.UserNamespace),
-		Host: len(uidmap) == 0 && len(gidmap) == 0,
+		Host: len(uidmap) == 0 && len(gidmap) == 0 && !useSlirp4netns,
 	}
 	// If the user specifically requested that we either use or don't use
 	// user namespaces, override that default.