Release 0.4.1 (#121) * Made typ didcomm message field optional When unpacking: - if present, value is correctly checked. - if not present it defaults to "application/didcomm-plain+json". When packing: - it is included. * Minor change * Routing keys are optional in service endpoint. * Bump version to 0.4.1 (#120) * Bump version to 0.4.1 --------- Co-authored-by: Sacha Kozma <sacha.kozma@gmail.com>