Bump com.diffplug.spotless from 6.19.0 to 6.20.0

Bumps com.diffplug.spotless from 6.19.0 to 6.20.0.

---
updated-dependencies:
- dependency-name: com.diffplug.spotless
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle.kts

@@ -4,7 +4,7 @@ plugins {
     kotlin("jvm") version kotlinVersion
     kotlin("plugin.allopen") version kotlinVersion
     kotlin("plugin.noarg") version kotlinVersion
-    id("com.diffplug.spotless") version "6.19.0"
+    id("com.diffplug.spotless") version "6.20.0"
     id("io.quarkus") version "3.2.3.Final"
     id("com.vaadin") version "24.1.4"
 }