Bump PyPDF to version 2 (#2755)

src/pretix/plugins/ticketoutputpdf/exporters.py

@@ -43,7 +43,7 @@ from django.db.models import Q
 from django.db.models.functions import Coalesce
 from django.utils.timezone import make_aware
 from django.utils.translation import gettext as _, gettext_lazy
-from PyPDF2.merger import PdfFileMerger
+from PyPDF2 import PdfMerger
 
 from pretix.base.exporter import BaseExporter
 from pretix.base.i18n import language
@@ -105,7 +105,7 @@ class AllTicketsPDF(BaseExporter):
         return d
 
     def render(self, form_data):
-        merger = PdfFileMerger()
+        merger = PdfMerger()
         qs = OrderPosition.objects.filter(
             order__event__in=self.events
         ).prefetch_related(