Warn instead of error for unused imports (apache#12588)

* warn not error on unused imports

* pre-commit error on clippy

Author: samuelcolvin

Cargo.toml

@@ -169,4 +169,3 @@ large_futures = "warn"
 
 [workspace.lints.rust]
 unexpected_cfgs = { level = "warn", check-cfg = ["cfg(tarpaulin)"] }
-unused_imports = "deny"

pre-commit.sh

@@ -25,6 +25,8 @@
 # This file be run directly:
 # $ ./pre-commit.sh
 
+set -e
+
 function RED() {
 	echo "\033[0;31m$@\033[0m"
 }