chore(deps): Update plugin spotless to v7

Author: renovate[bot]

gradle/libs.versions.toml

@@ -33,4 +33,4 @@ indra-checkstyle = { id = "net.kyori.indra.checkstyle", version.ref = "indra" }
 indra-licenserSpotless = { id = "net.kyori.indra.licenser.spotless", version.ref = "indra" }
 indra-sonatype = { id = "net.kyori.indra.publishing.sonatype", version.ref = "indra" }
 nexusPublish = { id = "io.github.gradle-nexus.publish-plugin", version = "2.0.0"}
-spotless = { id = "com.diffplug.spotless", version = "6.21.0" }
+spotless = { id = "com.diffplug.spotless", version = "7.1.0" }