"Is required" untranslatable

[maxxer]

Infos:

• Used Zammad version: 3.0.x
• Installation method (source, package, ..): Docker
• Operating system: Ubuntu 16.04
• Database + version: Docker
• Elasticsearch version: Docker

I was creating a new contact from within issue creation.

[MrGeneration]

is required currently can't be translated.
As we already have required in our list (and I also think this as a single word is totally enough, we also should change this).

If one word is enough, I'd prefer field required or field is required.

[mgruner]

Will be fixed with the upcoming Weblate migration in Zammad 5.1.