bcf - fix xsdata warning about deprecated argument in SerializerConfig

`pretty_print` was deprecated in 24.2 (https://github.com/tefra/xsdata/commit/2b01dbf6cf586e7d64e93ec7045dc17d2585e0de) and replaced with `indent`

src/bcf/src/bcf/xml_parser.py

@@ -17,7 +17,7 @@ def build_xml_parser(context: Optional[XmlContext] = None) -> XmlParser:
 def build_serializer(context: Optional[XmlContext] = None) -> XmlSerializer:
     """Return a serializer for an XML file."""
     return XmlSerializer(
-        config=SerializerConfig(pretty_print=True),
+        config=SerializerConfig(indent="  "),
         context=context or XmlContext(),
     )