Re-export core in codecs (#395)

It's impossible to use codecs without also importing core

Signed-off-by: Jiahao XU <[email protected]>

Author: NobodyXu

crates/compression-codecs/src/lib.rs

@@ -4,6 +4,8 @@
 
 use std::io::Result;
 
+pub use compression_core as core;
+
 #[cfg(feature = "brotli")]
 pub mod brotli;
 #[cfg(feature = "bzip2")]