Fix the screenshot URLs in the appstream XML

files/openmw.appdata.xml

@@ -23,19 +23,19 @@ Copyright 2020 Bret Curtis <psi29a@gmail.com>
  <launchable type="desktop-id">org.openmw.launcher.desktop</launchable>
  <screenshots>
   <screenshot type="default">
-   <image>https://wiki.openmw.org/images/b/b2/Openmw_0.11.1_launcher_1.png</image>
+   <image>https://wiki.openmw.org/images/Openmw_0.11.1_launcher_1.png</image>
    <caption>The OpenMW launcher</caption>
   </screenshot>
   <screenshot>
-   <image>https://wiki.openmw.org/images/f/f1/Screenshot_mournhold_plaza_0.35.png</image>
+   <image>https://wiki.openmw.org/images/0.40_Screenshot-Balmora_3.png</image>
    <caption>The Mournhold's plaza on OpenMW</caption>
   </screenshot>
   <screenshot>
-   <image>https://wiki.openmw.org/images/5/5b/Screenshot_Vivec_seen_from_Ebonheart_0.35.png</image>
+   <image>https://wiki.openmw.org/images/Screenshot_mournhold_plaza_0.35.png</image>
    <caption>Vivec seen from Ebonheart on OpenMW</caption>
   </screenshot>
   <screenshot>
-   <image>http://wiki.openmw.org/images/a/a3/0.40_Screenshot-Balmora_3.png</image>
+   <image>https://wiki.openmw.org/images/Screenshot_Vivec_seen_from_Ebonheart_0.35.png</image>
    <caption>Balmora at morning on OpenMW</caption>
   </screenshot>
  </screenshots>