chore(deps): bump kotlin.version from 2.0.21 to 2.1.0 in /demos

Bumps `kotlin.version` from 2.0.21 to 2.1.0.

Updates `org.jetbrains.kotlin:kotlin-bom` from 2.0.21 to 2.1.0
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v2.1.0/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.21...v2.1.0)

Updates `org.jetbrains.kotlin:kotlin-maven-plugin` from 2.0.21 to 2.1.0

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.jetbrains.kotlin:kotlin-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

demos/pom.xml

@@ -14,7 +14,7 @@
 		<project.reporting.outputEncoding>${project.build.sourceEncoding}</project.reporting.outputEncoding>
 		<maven.deploy.skip>true</maven.deploy.skip>
 
-		<kotlin.version>2.0.21</kotlin.version>
+		<kotlin.version>2.1.0</kotlin.version>
 		<kotlin.compiler.jvmTarget>${maven.compiler.source}</kotlin.compiler.jvmTarget>
 
 		<!-- overridden by submodule -->