Bump com.puppycrawl.tools:checkstyle from 10.17.0 to 10.21.1

Bumps [com.puppycrawl.tools:checkstyle](https://github.com/checkstyle/checkstyle) from 10.17.0 to 10.21.1.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](checkstyle/checkstyle@checkstyle-10.17.0...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] <support@github.com>

Author: dependabot[bot]

pom.xml

@@ -46,7 +46,7 @@
     <jenkins.baseline>2.440</jenkins.baseline>
     <jenkins.version>${jenkins.baseline}.3</jenkins.version>
     <powermock.version>1.6.1</powermock.version>
-    <checkstyle.version>10.17.0</checkstyle.version>
+    <checkstyle.version>10.21.1</checkstyle.version>
     <hpi.compatibleSinceVersion>2.0</hpi.compatibleSinceVersion>
   </properties>