fix ci bug?

Author: afox666

os/Makefile

@@ -40,7 +40,7 @@ build: env $(KERNEL_BIN) fs-img
 env:
 ifeq ($(OFFLINE),)
 	(rustup target list | grep "riscv64gc-unknown-none-elf (installed)") || rustup target add $(TARGET)
-	cargo install cargo-binutils
+	cargo install cargo-binutils --locked
 	rustup component add rust-src
 	rustup component add llvm-tools-preview
 endif