Use overlay

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

scripts/update.sh

@@ -4,7 +4,7 @@ set -o errexit
 set -o nounset
 set -o pipefail
 
-find . -type f -name "*.nix" | while read -r file; do
+find . -type f -name '*.nix' ! -path './submodules/*' | while read -r file; do
   update_command=$(grep -oP '^#\s*AUTO-UPDATE:\s*\K.+' "$file" || true)
   if [[ -n "$update_command" ]]; then
     echo "Running update command in: $file"