Add CheckDirection ReadWriters

New versions of Mill using UPickle 2.0.0 require ReadWriters for case objects and CheckDirection couldn't be set.

What's Changed

• Update mill-main to 0.10.5 by @scala-steward in #53
• Update scalafmt-core to 3.5.8 by @scala-steward in #54
• dep: start using mill-dependency-submission by @ckipp01 in #55
• Add ReadWriters for CheckDirection by @lolgab in #57

New Contributors

• @ckipp01 made their first contribution in #55

Full Changelog: 0.0.11...0.0.12