minor: expose decoding::Dictionary (#97)

Author: gstvg

ruzstd/src/decoding/mod.rs

@@ -6,6 +6,7 @@ mod streaming_decoder;
 
 pub use frame_decoder::{BlockDecodingStrategy, FrameDecoder};
 pub use streaming_decoder::StreamingDecoder;
+pub use dictionary::Dictionary;
 
 pub(crate) mod block_decoder;
 pub(crate) mod decode_buffer;