Bump com.puppycrawl.tools:checkstyle from 10.20.1 to 10.21.1

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.20.1 to 10.21.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](checkstyle/checkstyle@checkstyle-10.20.1...checkstyle-10.21.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pom.xml

@@ -25,7 +25,7 @@
 
         <junit.version>5.11.3</junit.version>
 
-        <checkstyle.version>10.20.2</checkstyle.version>
+        <checkstyle.version>10.21.1</checkstyle.version>
         <spotbugs.version>4.8.6</spotbugs.version>
         <pmd.version>7.7.0</pmd.version>
         <dependencycheck.version>10.0.4</dependencycheck.version>