Expose OdbPackwriter (#539)

Author: stoically

src/lib.rs

@@ -100,7 +100,7 @@ pub use crate::merge::{AnnotatedCommit, MergeOptions};
 pub use crate::message::{message_prettify, DEFAULT_COMMENT_CHAR};
 pub use crate::note::{Note, Notes};
 pub use crate::object::Object;
-pub use crate::odb::{Odb, OdbObject, OdbReader, OdbWriter};
+pub use crate::odb::{Odb, OdbObject, OdbPackwriter, OdbReader, OdbWriter};
 pub use crate::oid::Oid;
 pub use crate::packbuilder::{PackBuilder, PackBuilderStage};
 pub use crate::patch::Patch;