Upgrade Checkstyle 10.21.1 -> 10.21.2

See:
- https://checkstyle.sourceforge.io/releasenotes.html

pom.xml

@@ -923,7 +923,7 @@
                         <dependency>
                             <groupId>com.puppycrawl.tools</groupId>
                             <artifactId>checkstyle</artifactId>
-                            <version>10.21.1</version>
+                            <version>10.21.2</version>
                         </dependency>
                         <dependency>
                             <groupId>io.spring.nohttp</groupId>