ZUGFeRD-Manager 1.3.0

released version 1.3.0 🥳

• a lot of improvements under the hood for better maintainability
• support for multiple languages (closes #9)
• translated into English (closes #15, 🙏 @jstaerk)
• configure default country, default VAT rate & default currency
• integrated VAT rate for all EU countries and some other
• filter validation messages by type and severity (closes #10)
• copy single validation message into clipboard (closes #11)
• export validation results as JSON (closes #12)
• load PDF via drag & drop into create / check view (closes #13)
• update some dependencies