Open-web-calendar

- Add User-Agent header, see [Issue 225](https://github.com/niccokunzmann/open-web-calendar/issues/225).
- Close security vulnerability, [Pull Request 223](https://github.com/niccokunzmann/open-web-calendar/pull/223)
- Update German, Welsh, Croatian

- Add a dropdown to choose another time zone to view the calendar in the about screen, see [Issue 213](https://github.com/niccokunzmann/open-web-calendar/issues/213).

- Update dependencies

- Improve Indonesian translation by Reza Almanda
- Improve Spanish translation by zyloj
- Improve Polish translation by Eryk Michalak
- Update dependencies
- Do not test Python 3.7 any more
- Test Python 3.11

- Improve French translation
- Update dependencies

- Add Croatian UI by Milo Ivir