The use of bytes for serializing and deserializing was incorrect. It means that the serializing and deserializing of ObjectId and the underyling git_ext::Oid, which tends to cause issues with consumers of the API.

Change the Serialize and Deserialize implementations to defer to the git_ext::Oid implementations.

Add qcheck tests to ensure that these two types are compatible.

Changes:

• maintain compatibility with deserializing bytes