v4.8.1

Note - This release requires HA 2024.6.x

🧰 Maintenance

• Move writing of calendar file outside the thread - @RogerSelwyn
• Remove use of DEFAULT_TIME_ZONE constant - @RogerSelwyn

📚 Documentation

• Update README.md - @RogerSelwyn

🔖 Release

• Release v4.8.1 - @RogerSelwyn