build: update gnulib submodule to latest

Includes support for "shell-escape" from quotearg

diff --git a/gnulib b/gnulib
index 8be4b46b01cbcf7407b720571e5f455ed9fe7253..605b6330cc7fc9a679a1b0fa72f12eea0f1ea177 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 8be4b46b01cbcf7407b720571e5f455ed9fe7253
+Subproject commit 605b6330cc7fc9a679a1b0fa72f12eea0f1ea177