There is no main() in upload_to_pinata.py

`main()` is not included in the file. Should be:
```python
def main():
    with Path(filepath).open("rb") as fp:
        image_binary = fp.read()
        response = requests.post(
            PINATA_BASE_URL + endpoint,
            files={"file": (filename, image_binary)},
            headers=headers,
        )
        print(response.json())
```