Bump com.diffplug.spotless:spotless-maven-plugin from 2.30.0 to 2.39.0

Bumps [com.diffplug.spotless:spotless-maven-plugin](https://github.com/diffplug/spotless) from 2.30.0 to 2.39.0.
- [Changelog](https://github.com/diffplug/spotless/blob/main/CHANGES.md)
- [Commits](diffplug/spotless@lib/2.30.0...lib/2.39.0)

---
updated-dependencies:
- dependency-name: com.diffplug.spotless:spotless-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -78,7 +78,7 @@
         <groupId>com.diffplug.spotless</groupId>
         <artifactId>spotless-maven-plugin</artifactId>
         <!-- 2.31.0 + version requires JRE 11 -->
-        <version>2.30.0</version>
+        <version>2.39.0</version>
         <configuration>
           <java>
             <!--            <cleanthat/> This can be added after we drop java 8 support -->