0.5.0 alpha1 pre-release

Adds Marks, named ScalarValue annotations to characters within the Text object type. Marks provide support rich text formatting and serialization within Automerge. This release only updates the base code to support Marks, and has no convenience functions (yet) to interoperate with Swift - such as storing or retrieving AttributedStrings from Mark-annnotated Automerge Text objects.

What's Changed

• Update to automerge@0.5.0, implement marks by @alexjg in #39
• Sendable fix by @heckj in #41

Full Changelog: 0.3.2...0.5.0-alpha1