bootstrap: Update to 4.3.1

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/src/bootstrap b/src/bootstrap
index 3b558734382ce58b51e5fc676453bfd53bba9201..8fa0d3010112dca5dd6dd501173415856001ba8b 160000 (submodule)
--- a/src/bootstrap
+++ b/src/bootstrap
@@ -1 +1 @@
-Subproject commit 3b558734382ce58b51e5fc676453bfd53bba9201
+Subproject commit 8fa0d3010112dca5dd6dd501173415856001ba8b