Bump com.puppycrawl.tools:checkstyle from 10.20.2 to 10.21.0 (#225)

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/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
...

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

Author: dependabot[bot]

pom.xml

@@ -42,7 +42,7 @@
     <junit.version>5.11.3</junit.version>
     <jackson.version>2.18.2</jackson.version>
     <log4j2.version>2.24.3</log4j2.version>
-    <puppycrawl.version>10.20.2</puppycrawl.version>
+    <puppycrawl.version>10.21.0</puppycrawl.version>
   </properties>
 
   <modules>