chore(deps): update plugin autonomousapps-testkit to v0.15 (#671)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

gradle/libs.versions.toml

@@ -49,7 +49,7 @@ kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
 kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
 gradle-publish = { id = "com.gradle.plugin-publish", version = "1.3.1" }
 grgit = { id = "org.ajoberstar.grgit", version = "5.3.2" }
-autonomousapps-testkit = { id = "com.autonomousapps.testkit", version = "0.14" }
+autonomousapps-testkit = { id = "com.autonomousapps.testkit", version = "0.15" }
 gr8 = { id = "com.gradleup.gr8", version = "0.11.2" }
 vanniktech-publish = { id = "com.vanniktech.maven.publish", version = "0.34.0" }