Merge pull request #1391 from scala-steward/update/sbt-scalafmt-2.5.6

Update sbt-scalafmt to 2.5.6

Author: mergify[bot]

project/plugins.sbt

@@ -4,7 +4,7 @@ addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.13.1")
 
 addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.11.2")
 
-addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.5")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.6")
 
 addSbtPlugin("io.github.sbt-doctest" % "sbt-doctest" % "0.12.2")