Update dependency com.diffplug.spotless to v8

Author: renovate[bot]

gradle/libs.versions.toml

@@ -2,7 +2,7 @@
 doma = "3.14.0"
 kotlin = "2.4.10"
 junit = "5.14.4"
-spotless = "7.2.1"
+spotless = "8.8.0"
 doma-codegen = "3.2.2"
 doma-compile = "4.0.3"
 h2 = "2.4.240"