chore: bump org.jetbrains.kotlin:kotlin-gradle-plugin

Bumps [org.jetbrains.kotlin:kotlin-gradle-plugin](https://github.com/JetBrains/kotlin) from 1.8.10 to 1.8.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.10...v1.8.21)

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

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

Author: dependabot[bot]

build.gradle

@@ -11,7 +11,7 @@ buildscript {
     dependencies {
         classpath 'com.android.tools.build:gradle:7.4.1'
         classpath 'com.mparticle:android-kit-plugin:' + project.version
-        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.10'
+        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.21'
     }
 }