Update dependency com.diffplug.spotless to v8.6.0 (#4880)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

gradle/libs.versions.toml

@@ -35,7 +35,7 @@ serverlib = "2.3.7"
 # Gradle plugins
 shadow = "9.4.2"
 grgit = "4.1.1"
-spotless = "8.5.1"
+spotless = "8.6.0"
 publish = "0.36.0"
 runPaper = "3.0.2"