Cease using deprecated runc userlookup

Instead switch to github.com/moby/sys/user, which we already had
as an indirect dependency.

Signed-off-by: Matt Heon <mheon@redhat.com>

libpod/container_internal_common.go

@@ -47,7 +47,7 @@ import (
 	"github.com/containers/storage/pkg/lockfile"
 	stypes "github.com/containers/storage/types"
 	securejoin "github.com/cyphar/filepath-securejoin"
-	runcuser "github.com/opencontainers/runc/libcontainer/user"
+	runcuser "github.com/moby/sys/user"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/opencontainers/runtime-tools/generate"
 	"github.com/opencontainers/selinux/go-selinux"

libpod/oci_conmon_exec_freebsd.go

@@ -3,7 +3,7 @@
 package libpod
 
 import (
-	"github.com/opencontainers/runc/libcontainer/user"
+	"github.com/moby/sys/user"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 )
 

libpod/oci_conmon_exec_linux.go

@@ -4,7 +4,7 @@ package libpod
 
 import (
 	"github.com/containers/common/pkg/capabilities"
-	"github.com/opencontainers/runc/libcontainer/user"
+	"github.com/moby/sys/user"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 )