Update submodule `tests/extfs.d`

  > Fix(torrent): `encoding` is integer like `866`

diff --git a/tests/extfs.d b/tests/extfs.d
index b8a53129ab6b703de39237fce3d18ca97fe96b03..c815b201430dd7af725bba6b9dcac38662ffc0de 160000 (submodule)
--- a/tests/extfs.d
+++ b/tests/extfs.d
@@ -1 +1 @@
-Subproject commit b8a53129ab6b703de39237fce3d18ca97fe96b03
+Subproject commit c815b201430dd7af725bba6b9dcac38662ffc0de