Update release date

Author: ryonakano

data/granite.metainfo.xml.in

@@ -27,7 +27,7 @@
   <update_contact>contact_at_elementary.io</update_contact>
 
   <releases>
-    <release version="7.7.0" date="2025-09-23" urgency="medium">
+    <release version="7.7.0" date="2025-09-28" urgency="medium">
       <description>
         <p>New Icons:</p>
         <ul>