fix apt-get-update for non-English locale

https://forums.kicksecure.com/t/systemcheck-reports-warning-debian-package-update-check-result-apt-get-reports-that-packages-can-be-updated-but-system-is-already-fully-upgraded/785

usr/libexec/security-misc/apt-get-update

@@ -8,6 +8,8 @@ set -o nounset
 set -o errtrace
 set -o pipefail
 
+export LANG=C
+
 write_pid_file() {
   [[ -z "${TMP:-}" ]] && error "TMP is unset"
   safe-rm -rf "$TMP/security-misc-apt-get-update-pid";