chore: bump plugin.spring in /spring-graphql-rsocket-kotlin-co (#2998)

Bumps [plugin.spring](https://github.com/JetBrains/kotlin) from 2.0.21 to 2.1.0.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.21...v2.1.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

spring-graphql-rsocket-kotlin-co/build.gradle.kts

@@ -8,7 +8,7 @@ plugins {
 	id("io.spring.dependency-management") version "1.1.6"
 
 	kotlin("jvm") version "2.1.0"
-	kotlin("plugin.spring") version "2.0.21"
+	kotlin("plugin.spring") version "2.1.0"
 }
 
 group = "com.example"