Fix error for cargo check --workspace --all-targets

This prevents rust-analyzer from showing an error for the panic-handler
crate.

Author: bjorn3

crates/panic-handler/Cargo.toml

@@ -5,4 +5,8 @@ authors = ["Alex Crichton <[email protected]>"]
 edition = "2021"
 publish = false
 
+[lib]
+test = false
+bench = false
+
 [dependencies]