Fix homepage

src/data/org.kde.kmail2.appdata.xml

@@ -313,7 +313,7 @@
   </description>
   <url type="bugtracker">https://bugs.kde.org/enter_bug.cgi?format=guided&amp;product=kmail2</url>
   <url type="help">https://docs.kde.org/?application=kmail2</url>
-  <url type="homepage">https://kontact.kde.org/components/kmail.html</url>
+  <url type="homepage">https://kontact.kde.org/components/kmail/</url>
   <screenshots>
     <screenshot type="default">
       <image>https://kontact.org/assets/img/appstream/kontact-kmail.png</image>