Remove trailing dot from image caption

Flathub doesn't like that

src/app/org.kde.itinerary.appdata.xml

@@ -508,7 +508,7 @@
       <image width="480" height="720" type="source">https://cdn.kde.org/screenshots/itinerary/kde-itinerary-train-station-platform-map.png</image>
     </screenshot>
     <screenshot>
-      <caption>Train station map showing real-time availability of rental bikes.</caption>
+      <caption>Train station map showing real-time availability of rental bikes</caption>
       <caption xml:lang="ca">Mapa de l'estació de tren que mostra la disponibilitat en temps real de les bicicletes de lloguer</caption>
       <caption xml:lang="ca-valencia">Mapa de l'estació de tren que mostra la disponibilitat en temps real de les bicicletes de lloguer</caption>
       <caption xml:lang="en-GB">Train station map showing real-time availability of rental bikes.</caption>