Update sbt-scalafmt to 2.5.6

[scala-steward]

About this PR

📦 Updates org.scalameta:sbt-scalafmt from 2.5.5 to 2.5.6

📜 GitHub Release Notes - Version Diff

Usage

✅ Please merge!

I'll automatically update this PR to resolve conflicts as long as you don't change it yourself.

If you'd like to skip this version, you can just close this PR. If you have any feedback, just mention me in the comments below.

Configure Scala Steward for your repository with a .scala-steward.conf file.

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⚙ Adjust future updates

Add this to your .scala-steward.conf file to ignore future updates of this dependency:

updates.ignore = [ { groupId = "org.scalameta", artifactId = "sbt-scalafmt" } ]

Or, add this to slow down future updates of this dependency:

dependencyOverrides = [{
  pullRequests = { frequency = "30 days" },
  dependency = { groupId = "org.scalameta", artifactId = "sbt-scalafmt" }
}]

^{labels: sbt-plugin-update, early-semver-patch, semver-spec-patch, commit-count:1}

[what-the-diff]

PR Summary

• Upgraded sbt-scalafmt plugin
  The version of the sbt-scalafmt plugin, a tool that helps improve the formatting of our code, has been updated from 2.5.5 to 2.5.6. This update will ensure we are using the latest, most optimized version of the tool, offering potential enhancements and bug fixes.

[jchapuis]

Superseded by #518, which consolidates all outstanding dependency upgrades to their latest stable versions (and fixes the pre-existing versionPolicyCheck failure that was breaking CI on every Steward PR). Closing as no longer needed.