Update dependency com.puppycrawl.tools:checkstyle to v10.21.0

Author: renovate[bot]

pom.xml

@@ -80,7 +80,7 @@
 
         <checkstyle.maxAllowedViolations>10</checkstyle.maxAllowedViolations>
 
-        <com.puppycrawl.checkstyle.version>10.20.1</com.puppycrawl.checkstyle.version>
+        <com.puppycrawl.checkstyle.version>10.21.0</com.puppycrawl.checkstyle.version>
         <fasterxml.jackson.version>2.18.1</fasterxml.jackson.version>
         <tagchowder.version>2.0.29</tagchowder.version>