Bump com.puppycrawl.tools:checkstyle in the maven group

Bumps the maven group with 1 update: [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle).


Updates `com.puppycrawl.tools:checkstyle` from 10.20.2 to 10.21.0
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](checkstyle/checkstyle@checkstyle-10.20.2...checkstyle-10.21.0)

---
updated-dependencies:
- dependency-name: com.puppycrawl.tools:checkstyle
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: maven
...

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

pom.xml

@@ -106,7 +106,7 @@
             <dependency>
               <groupId>com.puppycrawl.tools</groupId>
               <artifactId>checkstyle</artifactId>
-              <version>10.20.2</version>
+              <version>10.21.0</version>
             </dependency>
           </dependencies>
         </plugin>