Bump info.solidsoft.gradle.pitest:gradle-pitest-plugin

Bumps info.solidsoft.gradle.pitest:gradle-pitest-plugin from 1.9.11 to 1.15.0.

---
updated-dependencies:
- dependency-name: info.solidsoft.gradle.pitest:gradle-pitest-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

buildSrc/build.gradle.kts

@@ -3,6 +3,6 @@ plugins { `kotlin-dsl` }
 repositories { gradlePluginPortal() }
 
 dependencies {
-  implementation("info.solidsoft.gradle.pitest:gradle-pitest-plugin:1.9.11")
+  implementation("info.solidsoft.gradle.pitest:gradle-pitest-plugin:1.15.0")
   implementation("com.diffplug.spotless:spotless-plugin-gradle:6.18.0")
 }