Move errdefs to pkg/errdefs

Signed-off-by: Derek McGowan <derek@mcg.dev>

core/leases/proxy/manager.go

@@ -21,7 +21,7 @@ import (
 
 	leasesapi "github.com/containerd/containerd/v2/api/services/leases/v1"
 	"github.com/containerd/containerd/v2/core/leases"
-	"github.com/containerd/containerd/v2/errdefs"
+	"github.com/containerd/containerd/v2/pkg/errdefs"
 	"github.com/containerd/containerd/v2/protobuf"
 )