Bump plugin.spring from 1.6.21 to 1.9.0 in /reviews-dgs

Bumps [plugin.spring](https://github.com/JetBrains/kotlin) from 1.6.21 to 1.9.0.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.6.21...v1.9.0)

---
updated-dependencies:
- dependency-name: plugin.spring
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

reviews-dgs/build.gradle.kts

@@ -18,7 +18,7 @@
 plugins {
 	id("org.springframework.boot") version "2.6.7"
 	id("io.spring.dependency-management") version "1.0.12.RELEASE"
-	kotlin("plugin.spring") version "1.6.21"
+	kotlin("plugin.spring") version "1.9.0"
 	id("java")
 	id("com.netflix.dgs.codegen") version "5.5.0"
 }