FIX: return list containing single xml tag element

src/caoscrawler/xml_converter.py

@@ -67,7 +67,7 @@ class XMLFileConverter(SimpleFileConverter):
                     "Error during the validation of the XML file:\n"
                     f"{element.path}\n" + err.message)
 
-        return XMLTagElement(xml.getroot())
+        return [XMLTagElement(xml.getroot())]
 
 
 class XMLTagConverter(Converter):