Add missing SHELL build-arg

Change-Id: Ic645c0411928f8b69c4d5b21a90462170576e7bc
diff --git a/crates/passwd/Cargo.toml b/crates/passwd/Cargo.toml
new file mode 100644
index 0000000..25b3dc1
--- /dev/null
+++ b/crates/passwd/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "passwd"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+thiserror = "2.0.11"