v3.0.0

• Resolve #49 : CC and BCC recipients can now be personalized via the add-on side panel. Use placeholders to designate them: e.g., {{cc}} and {{bcc}}
• Resolve #60 : Debug mode is now available at the bottom-most part of the Advanced Settings section in the add-on side panel. When enabled, details of the settings and a simple & personal log for each action are sent to the user in form of an email. This feature utilizes the Apps Script method MailApp.sendEmail(), which requires an addition to the OAuth scope that the add-on requests from the user: https://www.googleapis.com/auth/script.send_mail = Send email as you, or in Japanese, ユーザー本人に代わってのメールの送信
• Resolve #62 : This is the biggest update from v2; because there is a 30-second limit to the Card Service actions in Google Workspace Add-ons, an Exceeded maximum execution time was returned for a recipient list of approx. 50 or more rows. To work around this issue, a time-based triggering of a post-process function has been implemented. Note that there are still some issues left at #68
• Resolve #69 : Subsequent to the changes addressing #62, the draft ID of the template Gmail draft is now carried over to the post-process to avoid merged emails being falsely recognized as template drafts having non-unique subjects.

Misc

• Added CODE_OF_CONDUCT.md