update submodule to 1.2.8-1

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/ifupdown2 b/ifupdown2
index e1aa03b0314d55e1175f0f1bf8859f048d52e4f8..29369842c0faec3c9824177f9e7b203e11d16a51 160000 (submodule)
--- a/ifupdown2
+++ b/ifupdown2
@@ -1 +1 @@
-Subproject commit e1aa03b0314d55e1175f0f1bf8859f048d52e4f8
+Subproject commit 29369842c0faec3c9824177f9e7b203e11d16a51