Bump com.github.siom79.japicmp:japicmp from 0.18.3 to 0.21.1

Bumps [com.github.siom79.japicmp:japicmp](https://github.com/siom79/japicmp) from 0.18.3 to 0.21.1.
- [Release notes](https://github.com/siom79/japicmp/releases)
- [Changelog](https://github.com/siom79/japicmp/blob/master/release.py)
- [Commits](siom79/japicmp@japicmp-base-0.18.3...japicmp-base-0.21.1)

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

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

pom.xml

@@ -101,7 +101,7 @@
       <dependency>
         <groupId>com.github.siom79.japicmp</groupId>
         <artifactId>japicmp</artifactId>
-        <version>0.18.3</version>
+        <version>0.21.1</version>
       </dependency>
       <dependency>
         <groupId>org.slf4j</groupId>