Bump org.scala-lang:scala-library from 2.13.14 to 2.13.15

Bumps [org.scala-lang:scala-library](https://github.com/scala/scala) from 2.13.14 to 2.13.15.
- [Release notes](https://github.com/scala/scala/releases)
- [Commits](scala/scala@v2.13.14...v2.13.15)

---
updated-dependencies:
- dependency-name: org.scala-lang:scala-library
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle

@@ -25,7 +25,7 @@ dependencies {
 
   compile 'com.google.code.gson:gson:2.11.0'
 
-  testCompile 'org.scala-lang:scala-library:2.13.14'
+  testCompile 'org.scala-lang:scala-library:2.13.15'
   testCompile 'org.scalatest:scalatest_2.11:3.3.0-SNAP4'
   testCompile 'org.apache.kafka:kafka-streams-test-utils:3.8.0'
   testCompile group: 'junit', name: 'junit', version: '4.13.2'