Bump apps/zammad from `ff5f175` to `900d8fc`
Bump apps/zammad from `ff5f175` to `900d8fc`

Bumps [apps/zammad](https://github.com/zammad/zammad) from `ff5f175` to `900d8fc`.
- [Release notes](https://github.com/zammad/zammad/releases)
- [Commits](https://github.com/zammad/zammad/compare/ff5f1756406d3394e7157a1c00a316abcfe77aab...900d8fcd44f9b4c10cea7f8d5af24d47acf9cc2e)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
eliotsykes/real-world-rails