Update appcast.xml

Author: LocNguyenHuu

Appcast/appcast.xml

@@ -1,4 +1,4 @@
-<?xml version="1.0" standalone="yes"?>
+<?xml version="1.0" encoding="utf-8"?>
 <rss xmlns:sparkle="http://www.andymatuschak.org/xml-namespaces/sparkle" version="2.0">
     <channel>
         <title>HelperX</title>
@@ -11,4 +11,4 @@
             <enclosure url="https://github.com/HelperXApp/HelperX/blob/main/Appcast/HelperX.dmg" length="8344794" type="application/octet-stream" sparkle:edSignature="aNdbp/KKApigrMKpSg2iX+GMNV8r+O9sBpjubjv6eCpYvaRS8TNCeFxCnb0qXE7+QJ+pPyFMfxB4yAa3iv8jBQ=="/>
         </item>
     </channel>
-</rss>
+</rss>