Replace brick shape by square

From polygon, was very upgly when colliding with corners.

godot/scenes/main.tscn

@@ -21,8 +21,8 @@ extents = Vector2( 300, 50 )
 [sub_resource type="RectangleShape2D" id=4]
 extents = Vector2( 200, 50 )
 
-[sub_resource type="ConvexPolygonShape2D" id=5]
-points = PoolVector2Array( 0, 0, 40, 0, 40, 20, 0, 20 )
+[sub_resource type="RectangleShape2D" id=7]
+extents = Vector2( 20, 10 )
 
 [sub_resource type="TileSet" id=6]
 0/name = "brik.png 0"
@@ -37,8 +37,8 @@ points = PoolVector2Array( 0, 0, 40, 0, 40, 20, 0, 20 )
 "autotile_coord": Vector2( 0, 0 ),
 "one_way": false,
 "one_way_margin": 1.0,
-"shape": SubResource( 5 ),
-"shape_transform": Transform2D( 1, 0, 0, 1, 0, 0 )
+"shape": SubResource( 7 ),
+"shape_transform": Transform2D( 1, 0, 0, 1, 20, 10 )
 } ]
 0/z_index = 0