Update checkstyle to 8.18

Author: adangel

pom.xml

@@ -202,7 +202,7 @@
             <dependency>
               <groupId>com.puppycrawl.tools</groupId>
               <artifactId>checkstyle</artifactId>
-              <version>8.12</version>
+              <version>8.18</version>
             </dependency>
             <dependency>
               <groupId>net.sourceforge.pmd</groupId>