pycolmap: Point2D.point3D_id cannot be assigned

```
>>> import pycolmap
>>> p = pycolmap.Point2D()
>>> p.point3D_id = -1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: (): incompatible function arguments. The following argument types are supported:
    1. (self: pycolmap._core.Point2D, arg0: int) -> None

Invoked with: Point2D(xy=[0, 0], point3D_id=-1), -1
```