Bump com.diffplug.spotless:spotless-maven-plugin from 3.8.0 to 3.9.0 (#75)

Bumps [com.diffplug.spotless:spotless-maven-plugin](https://github.com/diffplug/spotless) from 3.8.0 to 3.9.0.
- [Release notes](https://github.com/diffplug/spotless/releases)
- [Changelog](https://github.com/diffplug/spotless/blob/main/CHANGES.md)
- [Commits](diffplug/spotless@maven/3.8.0...maven/3.9.0)

---
updated-dependencies:
- dependency-name: com.diffplug.spotless:spotless-maven-plugin
  dependency-version: 3.9.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pom.xml

@@ -89,7 +89,7 @@
       <plugin>
         <groupId>com.diffplug.spotless</groupId>
         <artifactId>spotless-maven-plugin</artifactId>
-        <version>3.8.0</version>
+        <version>3.9.0</version>
         <configuration>
           <java>
             <googleJavaFormat>