2.5.0 Release

Incompat note: that reset_on_fork flag was removed at this release.

What's Changed

• Update documentation of sparse file cache by @kuenishi in #291
• Flake8 skip for Python 3.7 by @kuenishi in #295
• Refine pfio.cache.HTTPCache by @y1r in #293
• S3 + zipfile on fork-server multiprocessing by @y1r in #292
• Remove reset_on_fork parameter by @y1r in #297
• Bump version by @kuenishi in #298

Full Changelog: 2.4.0...2.5.0