Correction erreur balise header xml

src/extract/formatter.js

@@ -2,7 +2,7 @@ const Entities = require('html-entities').AllHtmlEntities;
 const entities = new Entities();
 
 module.exports.toXml = function (name, data) {
-    let xml = '<?xml version="1.0" encoding="UTF-8">\n';
+    let xml = '<?xml version="1.0" encoding="UTF-8"?>\n';
     xml += '<extract>\n';
     xml += `\t<name>${entities.decode(name)}</name>\n`;
     xml += '\t<coauthors>\n';