Update appcast.xml

Author: intitni

appcast.xml

@@ -3,6 +3,18 @@
   <channel>
     <title>Copilot for Xcode</title>
 
+    <item>
+      <title>0.28.0</title>
+      <pubDate>Mon, 04 Dec 2023 16:04:23 +0800</pubDate>
+      <sparkle:version>290</sparkle:version>
+      <sparkle:shortVersionString>0.28.0</sparkle:shortVersionString>
+      <sparkle:minimumSystemVersion>12.0</sparkle:minimumSystemVersion>
+      <sparkle:releaseNotesLink>
+        https://github.com/intitni/CopilotForXcode/releases/tag/0.28.0
+      </sparkle:releaseNotesLink>
+      <enclosure url="https://github.com/intitni/CopilotForXcode/releases/download/0.28.0/Copilot.for.Xcode.app.zip" length="36956518" type="application/octet-stream" sparkle:edSignature="YC5/0zEGAC+COmqpc2FIXt41wkMHRXtoH6NIKfbsu86F7HhwuOEQhieEoxU/MnoASOShuDIUVKWGJqv51azYAw=="/>
+    </item>
+
     <item>
       <title>0.27.1</title>
       <pubDate>Sat, 18 Nov 2023 12:46:36 +0800</pubDate>