Change build type for Big back into release mode

Author: jhaye

Rust/Savina/src/micro/Big.lf

@@ -25,7 +25,7 @@
 
 
 target Rust {
-    build-type: Debug,
+    build-type: Release,
     cargo-features: [ "cli" ],
     rust-include: "../lib/pseudo_random.rs",
 };