cargo lock updater: use git ls-files

cargo-lock-updater

@@ -1,6 +1,5 @@
 #!/usr/bin/env zsh
-
-find . -type f -name 'Cargo.lock' -print0 | while IFS=$'\0' read -r -d '' file; do
+for file in $(git ls-files | grep Cargo.lock); do
 	(cd "$(dirname "$file")" && cargo update -wq)
 	git add $file
 done