Bump com.diffplug.spotless:spotless-maven-plugin from 2.30.0 to 3.2.1

Bumps [com.diffplug.spotless:spotless-maven-plugin](https://github.com/diffplug/spotless) from 2.30.0 to 3.2.1.
- [Release notes](https://github.com/diffplug/spotless/releases)
- [Changelog](https://github.com/diffplug/spotless/blob/main/CHANGES.md)
- [Commits](diffplug/spotless@lib/2.30.0...maven/3.2.1)

---
updated-dependencies:
- dependency-name: com.diffplug.spotless:spotless-maven-plugin
  dependency-version: 3.2.1
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

pom.xml

@@ -147,7 +147,7 @@
         <groupId>com.diffplug.spotless</groupId>
         <artifactId>spotless-maven-plugin</artifactId>
         <!-- 2.31.0 + version requires JRE 11 -->
-        <version>2.30.0</version>
+        <version>3.2.1</version>
         <configuration>
           <java>
             <!--            <cleanthat/> This can be added after we drop java 8 support -->