Update sbt-scalafmt to 2.5.6

Signed-off-by: Scala Steward <scala_steward@virtuslab.com>

Author: scala-steward

project/plugins.sbt

@@ -9,7 +9,7 @@ addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")
 addSbtPlugin("com.github.sbt" % "sbt-site" % "1.7.0")
 addSbtPlugin("io.kevinlee" % "sbt-github-pages" % "0.16.0")
 addSbtPlugin("nl.gn0s1s" % "sbt-dotenv" % "3.2.0")
-addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.5")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.6")
 addSbtPlugin("org.scoverage" % "sbt-scoverage" % "2.3.1")
 addSbtPlugin("org.wartremover" % "sbt-wartremover" % "3.3.2")
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.12.2")