Re-export the sigma-compiler crate so that it doesn't need to be an explicit dependency in your Cargo.toml file

Users of the cmz crate no longer have to explicitly list sigma-compiler
as a dependency in Cargo.toml

src/lib.rs

@@ -14,6 +14,7 @@ use rand::RngCore;
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 pub use serde_with::serde_as;
 use serde_with::{DeserializeAs, SerializeAs};
+pub use sigma_compiler;
 use sigma_compiler::*;
 use thiserror::Error;