Bump japicmp-maven-plugin from 0.9.3 to 0.15.4

Bumps [japicmp-maven-plugin](https://github.com/siom79/japicmp) from 0.9.3 to 0.15.4.
- [Release notes](https://github.com/siom79/japicmp/releases)
- [Changelog](https://github.com/siom79/japicmp/blob/master/release.py)
- [Commits](siom79/japicmp@japicmp-base-0.9.3...japicmp-base-0.15.4)

---
updated-dependencies:
- dependency-name: com.github.siom79.japicmp:japicmp-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -336,7 +336,7 @@
         <version.help.plugin>3.2.0</version.help.plugin>
         <version.install.plugin>2.5.2</version.install.plugin>
         <version.io.takari.maven>0.7.7</version.io.takari.maven>
-        <version.japicmp.plugin>0.9.3</version.japicmp.plugin>
+        <version.japicmp.plugin>0.15.4</version.japicmp.plugin>
         <version.jar.plugin>3.2.0</version.jar.plugin>
         <version.javadoc.plugin>3.2.0</version.javadoc.plugin>
         <version.jdeps.plugin>0.5.1</version.jdeps.plugin>