Exception occurs in InvoiceMapper when mapping invoice from Twinfield

[willemo]

When the incoming invoice from Twinfield has a performancetype tag, the mapper tries to use setPerformanceType() on the InvoiceLine to set the value. The setter expects the PerformanceType enum, but the value from the XML document is never cast to the enum and passed as a string.

The following exception then occurs:

Argument 1 passed to PhpTwinfield\InvoiceLine::setPerformanceType() must be an instance of PhpTwinfield\Enums\PerformanceType or null, string given, called in vendor/php-twinfield/twinfield/src/Mappers/InvoiceMapper.php on line 107

This means either the method signature should allow strings to be passed, or the string from the XML document should be cast to the PerformanceType enum before calling the setter.

[willemstuursma]

Hi @willemo, PR's welcome for this.