chore(deps): update dependency com.puppycrawl.tools:checkstyle to v10.21.4

Author: renovate[bot]

backend/pom.xml

@@ -482,7 +482,7 @@
           <dependency>
             <groupId>com.puppycrawl.tools</groupId>
             <artifactId>checkstyle</artifactId>
-            <version>10.21.3</version>
+            <version>10.21.4</version>
           </dependency>
         </dependencies>
         <configuration>