v0.4.0

Added

• content_hash field for the LogEntry records with the hash of the content field, if included in the message.
• Command base class for all the classes representing GraphQL queries or mutations sent to the Bulletin Board.
• open_ballot_box and close_ballot_box methods to the Decidim::BulletinBoard::Client.

Changed

• New format for the messages: iat, message_id and Bulletin Board fields in the root message, and content for the Voting Scheme messages.
• Improved consistency between methods included by Decidim::BulletinBoard::Client.