Joe Harrison

Fixes Issue #6

After upgraded scrapy, The follow warning occurs on every request that uses crawl_once: ``` 2022-10-28 15:54:21 [py.warnings] WARNING: /scrapyd/venv/lib/python3.9/site-packages/scrapy_crawl_once/middlewares.py:96: ScrapyDeprecationWarning: Call to deprecated function scrapy.utils.request.request_fingerprint(). If you are using this...