Update dependency com.diffplug.spotless to v8.4.0 (#270)

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

Author: renovate[bot]

gradle/libs.versions.toml

@@ -8,7 +8,7 @@ bstats = "3.0.0"
 
 # Gradle plugins
 shadow = "9.3.2"
-spotless = "8.3.0"
+spotless = "8.4.0"
 bukkityml = "0.6.0"
 minotaur = "2.8.10"