Renamed file error

In [`test_process_osm.py`](https://github.com/aicenter/road-graph-tool/blob/main/python/tests/test_process_osm.py) on line 95: 
```python
input_file = str(parent_dir) + "/data/test.osm"
```
should be
```python
input_file = str(parent_dir) + "/data/bbox_test.osm"
```