Add "Bought" to concordance list for entry types

src/MDConcEntryTypes.php

@@ -57,6 +57,7 @@ final class MDConcEntryTypes implements MDImporterConcordanceListInterface {
         "3Ankauf" => "2",
         "Ankauf Peitz" => "2",
         "Ankauf Sagar" => "2",
+        "Bought" => "2",
         "Bestellung" => "2",
         "Kauf Verein" => "2",
         "Einkauf" => "2",