release: update appcast for v1.8.6

Author: JerryZLiu

docs/appcast.xml

@@ -3,6 +3,18 @@
   <channel>
     <title>Dayflow Updates</title>
     <language>en</language>
+    <item>
+      <title>Version 1.8.6</title>
+      <pubDate>Sun, 15 Mar 2026 06:27:31 +0000</pubDate>
+      <enclosure url="https://github.com/JerryZLiu/Dayflow/releases/download/v1.8.6/Dayflow.dmg"
+                 sparkle:version="97"
+                 sparkle:shortVersionString="1.8.6"
+                 length="37987889"
+                 type="application/octet-stream"
+                 sparkle:edSignature="IlAlySq7EiZ7kxs5es0rfKsJRStkGrokhX0gsJR42TM63JA4G9F+uErtfZCxq/35zDvrcT0Cz9hdEaIKa327BA=="/>
+      <sparkle:minimumSystemVersion>13.0</sparkle:minimumSystemVersion>
+      <releaseNotesLink>https://github.com/JerryZLiu/Dayflow/releases/tag/v1.8.6</releaseNotesLink>
+    </item>
     <item>
       <title>Version 1.8.5</title>
       <pubDate>Mon, 09 Mar 2026 08:29:58 +0000</pubDate>