Version 3.0.0

• Added ISO format #8 (@rambowm)
• Dropped Redmine 4.0 support
• Redmine 4.1 support
• Fixed automatic serial number when copying issue
  • チケットコピー時に自動採番されない #6 (@subaru019)
  • Review comments for this plugin on redmine.org (Jorge Garcia, Quan VN, qn wang)