Bump spotless-maven-plugin in /.github/planetiler-examples-dependabot (#462)

Bumps [spotless-maven-plugin](https://github.com/diffplug/spotless) from 2.30.0 to 2.31.0.
- [Release notes](https://github.com/diffplug/spotless/releases)
- [Changelog](https://github.com/diffplug/spotless/blob/main/CHANGES.md)
- [Commits](https://github.com/diffplug/spotless/compare/lib/2.30.0...lib/2.31.0)

---
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>

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

pom.xml

@@ -177,7 +177,7 @@
       <plugin>
         <groupId>com.diffplug.spotless</groupId>
         <artifactId>spotless-maven-plugin</artifactId>
-        <version>2.30.0</version>
+        <version>2.31.0</version>
         <configuration>
           <java>
             <importOrder/>