Update appcast.xml

Author: intitni

appcast.xml

@@ -3,6 +3,18 @@
   <channel>
     <title>Copilot for Xcode</title>
 
+    <item>
+      <title>0.28.3</title>
+      <pubDate>Tue, 12 Dec 2023 14:29:58 +0800</pubDate>
+      <sparkle:version>293</sparkle:version>
+      <sparkle:shortVersionString>0.28.3</sparkle:shortVersionString>
+      <sparkle:minimumSystemVersion>12.0</sparkle:minimumSystemVersion>
+      <sparkle:releaseNotesLink>
+        https://github.com/intitni/CopilotForXcode/releases/tag/0.28.3
+      </sparkle:releaseNotesLink>
+      <enclosure url="https://github.com/intitni/CopilotForXcode/releases/download/0.28.3/Copilot.for.Xcode.app.zip" length="36973011" type="application/octet-stream" sparkle:edSignature="fEi1llRa9nUVemxGr4mQtTLOkP4lTYqOm0j6qGMhoVtv1ySiklTdqit7PVW6tdQZc1iSpC7DZEFsxKq5+D4ZDA=="/>
+    </item>
+
     <item>
       <title>0.28.2</title>
       <pubDate>Mon, 04 Dec 2023 23:11:26 +0800</pubDate>