add missing import

Author: geritwagner

colrev/record/record_id_setter.py

@@ -19,6 +19,7 @@
 from colrev.constants import FieldValues
 from colrev.constants import IDPattern
 from colrev.constants import RecordState
+import colrev.record.record_prep
 
 # pylint: disable=too-few-public-methods