Fix screenshot url in appdata

Author: Mirko Brombin

data/com.github.linuxhubit.shouldidoit.appdata.xml.in

@@ -21,7 +21,7 @@
   </releases>
   <screenshots>
     <screenshot type="default">
-      <image>https://raw.githubusercontent.com/linuxhubit/discover/master/data/screenshot-1.png</image>
+      <image>https://raw.githubusercontent.com/linuxhubit/shouldidoit/master/data/screenshot-1.png</image>
     </screenshot>
   </screenshots>