Bump org.jetbrains.kotlin.jvm from 1.7.20 to 1.7.21 in /examples

Bumps [org.jetbrains.kotlin.jvm](https://github.com/JetBrains/kotlin) from 1.7.20 to 1.7.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.7.20...v1.7.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin.jvm
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

examples/spring-boot-kotlin-redis/build.gradle

@@ -1,6 +1,6 @@
 plugins {
     id("org.springframework.boot") version "2.7.5"
-    id("org.jetbrains.kotlin.jvm") version "1.7.20"
+    id("org.jetbrains.kotlin.jvm") version "1.7.21"
     id("org.jetbrains.kotlin.plugin.spring") version "1.7.21"
 }