appdata: improve URLs

- use https
- use canonical cdn screenshot location

src/org.kde.kgoldrunner.appdata.xml

@@ -333,7 +333,7 @@
     </ul>
   </description>
   <url type="bugtracker">https://bugs.kde.org/enter_bug.cgi?format=guided&amp;product=kgoldrunner</url>
-  <url type="help">http://docs.kde.org/?application=kgoldrunner</url>
+  <url type="help">https://docs.kde.org/?application=kgoldrunner</url>
   <url type="donation">https://www.kde.org/community/donations/?app=kgoldrunner&amp;source=appdata</url>
   <screenshots>
     <screenshot type="default">
@@ -360,7 +360,7 @@
       <caption xml:lang="x-test">xxPlaying KGoldrunnerxx</caption>
       <caption xml:lang="zh-CN">正在玩 KGoldrunner</caption>
       <caption xml:lang="zh-TW">KGoldrunner 遊玩畫面</caption>
-      <image>https://kde.org/images/screenshots/kgoldrunner.png</image>
+      <image>https://cdn.kde.org/screenshots/kgoldrunner/kgoldrunner.png</image>
     </screenshot>
   </screenshots>
   <project_group>KDE</project_group>