chore: Don't optimize build dependencies

Rust 1.41 shipped with the ability to specify optimization level
per dependency/dev-dependency.

This speeds up a full release build by ~20% on my machine.

Cargo.toml

@@ -7,3 +7,7 @@ members = [
     "web",
     "scanner",
 ]
+
+# Don't optimize build scripts and macros.
+[profile.dev.build-override]
+opt-level = 0