Added missing properties for several blocks

src/pocketmine/block/CobblestoneWall.php

@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
+use pocketmine\item\TieredTool;
 use pocketmine\math\AxisAlignedBB;
 use pocketmine\math\Vector3;
 
@@ -40,6 +41,10 @@ class CobblestoneWall extends Transparent{
 		return BlockToolType::TYPE_PICKAXE;
 	}
 
+	public function getToolHarvestLevel() : int{
+		return TieredTool::TIER_WOODEN;
+	}
+
 	public function getHardness() : float{
 		return 2;
 	}