v0.8.1 Minor bug fix release, change docker registry to ghcr.io

Switch to use ghcr.io docker container registry, and some minor bugfixes and latest dependencies.

What's Changed

• Migrate to GitHub Docker registry by @stepankuzmin in #602
• Use cargo sparse index in docker by @nyurik in #614
• Prepare for sub-crate publish, detection bug fix by @nyurik in #615

Full Changelog: v0.8.0...v0.8.1