Released version 2.0.0-alpha1

• Moved classes from Shoptet to Sunfox namespace
• Use PSR-4 autoloading
• Dropped PHP compatibility below 7.4
• Use strict types
• Added basic tests and PHPStan
• Class InvalidParameterException is now final [BR break]
• Class IbanUtilities is now final [BR break]
• Method IbanUtilities::computeIbanFromBankAccount() returns null instead of false on failure [BR break]
• Moved method DefaultAccount::getNumericLanguageCode() to IbanUtilities class and made it final [BR break]
• Moved variable $localeAlphabet from DefaultAccount to IbanUtilities class [BR break]
• Removed method __conctruct() from interface Account [BR break]
• Added method isValid() to interface Acount [BR break]
• Renamed SlovakiaAccount to SlovakAccount [BR break]
• Classes CzechAccount and SlovakAccount are now final [BR break]