Maintenance release:

- ⬆Update bookstack to v0.30.3
- ⬆Update composer to 1.10.15-r0
- ⬆Update php to 7.3.23-r0
- ⬆Update nginx to 1.18.0-r1
- ⬆Update mariadb-client to 10.4.15-r0

Questions? Join our Discord server! https://discord.me/hassioaddons

[Full Changelog][changelog]

[changelog]: https://github.com/hassio-addons/addon-bookstack/compare/v0.6.2...v0.6.3