v2.28.0-rc.3

• Improvement - BlockMutationType and BlockMutationEvent types exported
• Improvement - blocks.update(id, data) now can accept partial data object — it will update only passed properties, others will remain the same.
• Improvement - blocks.update(id, data) now will trigger onChange with only block-change event.
• Improvement - blocks.update(id, data) will return a promise with the BlockAPI object of the changed block.