Bump org.pitest:pitest-maven from 1.15.4 to 1.15.6

Bumps [org.pitest:pitest-maven](https://github.com/hcoles/pitest) from 1.15.4 to 1.15.6.
- [Release notes](https://github.com/hcoles/pitest/releases)
- [Commits](hcoles/pitest@1.15.4...1.15.6)

---
updated-dependencies:
- dependency-name: org.pitest:pitest-maven
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

pom.xml

@@ -74,7 +74,7 @@
         <version.weld-junit5>4.0.1.Final</version.weld-junit5>
 
         <version.jacoco-maven-plugin>0.8.11</version.jacoco-maven-plugin>
-        <version.pitest-maven>1.15.4</version.pitest-maven>
+        <version.pitest-maven>1.15.6</version.pitest-maven>
         <version.pitest-junit5-plugin>1.2.1</version.pitest-junit5-plugin>
 
         <sonar.coverage.jacoco.xmlReportPaths>target/site/jacoco/jacoco.xml</sonar.coverage.jacoco.xmlReportPaths>