Bump io.gitlab.arturbosch.detekt from 1.19.0 to 1.21.0

Bumps [io.gitlab.arturbosch.detekt](https://github.com/detekt/detekt) from 1.19.0 to 1.21.0.
- [Release notes](https://github.com/detekt/detekt/releases)
- [Commits](detekt/detekt@v1.19.0...v1.21.0)

---
updated-dependencies:
- dependency-name: io.gitlab.arturbosch.detekt
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

build.gradle.kts

@@ -11,7 +11,7 @@ plugins {
 
     id("net.nemerosa.versioning") version "2.15.1"
     id("org.jetbrains.dokka") version "1.7.20"
-    id("io.gitlab.arturbosch.detekt") version "1.19.0"
+    id("io.gitlab.arturbosch.detekt") version "1.21.0"
 }
 
 group = "dev.forst"