Fix: barbarians pillaging ancient ruins (#1720)

Co-authored-by: dumichno <57294813+dumichno@users.noreply.github.com>

core/src/com/unciv/ui/worldscreen/unit/UnitActions.kt

@@ -322,6 +322,7 @@ class UnitActions {
 
     fun canPillage(unit: MapUnit, tile: TileInfo): Boolean {
         if (tile.improvement == null || tile.improvement == Constants.barbarianEncampment
+                || tile.improvement == Constants.ancientRuins
                 || tile.improvement == "City ruins") return false
         val tileOwner = tile.getOwner()
         // Can't pillage friendly tiles, just like you can't attack them - it's an 'act of war' thing