chore(deps): bump com.puppycrawl.tools:checkstyle

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] <[email protected]>

pom.xml

@@ -48,7 +48,7 @@
         <maven-checkstyle-plugin.version>3.6.0</maven-checkstyle-plugin.version>
         <spring-javaformat.version>0.0.43</spring-javaformat.version>
 
-        <checkstyle.version>10.20.2</checkstyle.version>
+        <checkstyle.version>10.21.0</checkstyle.version>
 
         <check.dir>src/checkconfig</check.dir>
         <pmd.dir>${check.dir}/pmd</pmd.dir>