www/py-scrapy: Update to 2.5.0

Changelog: https://docs.scrapy.org/en/latest/news.html?highlight=news#scrapy-2-5-0-2021-04-06

This also removes/disables the experimental HTTP/2 support, there are
issues with Twisted and h2 at this moment which breaks scrapy.

PR: 256259
Approved by: maintainer timeout (skreuzer)