Update release date

Author: jeremypw

data/code.metainfo.xml.in

@@ -68,7 +68,7 @@
   <update_contact>contact_AT_elementary.io</update_contact>
 
   <releases>
-    <release version="8.1.0" date="2025-07-31" urgency="medium">
+    <release version="8.1.0" date="2025-08-01" urgency="medium">
       <description>
         <p>Improvements:</p>
         <ul>