Bump com.github.siom79.japicmp:japicmp-maven-plugin (#1839)

Bumps [com.github.siom79.japicmp:japicmp-maven-plugin](https://github.com/siom79/japicmp) from 0.25.5 to 0.25.6.
- [Release notes](https://github.com/siom79/japicmp/releases)
- [Changelog](https://github.com/siom79/japicmp/blob/master/release.py)
- [Commits](siom79/japicmp@japicmp-base-0.25.5...japicmp-base-0.25.6)

---
updated-dependencies:
- dependency-name: com.github.siom79.japicmp:japicmp-maven-plugin
  dependency-version: 0.25.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]

pom.xml

@@ -246,7 +246,7 @@
         <plugin>
           <groupId>com.github.siom79.japicmp</groupId>
           <artifactId>japicmp-maven-plugin</artifactId>
-          <version>0.25.5</version>
+          <version>0.25.6</version>
           <configuration>
             <oldVersion>
               <!-- We compare same module against 1.8.0 set as "baseline" -->