FR: Publish snapshots

Currently it's tedious to test unreleased versions of this library because it does not publish snapshots, would you consider enabling automatic publishing to sonatype's snapshots repo?

Start by locating ktfmt's build and publishing configuration and reviewing how releases are currently sent to Sonatype. Determine the existing snapshot repository and automation entry points, then verify that an unreleased build is published automatically and can be consumed from the snapshots repository.

Written by the indexing model from the issue text.