Upgrade Checkstyle 10.11.0 -> 10.12.0 (#651)

See:
- https://checkstyle.sourceforge.io/releasenotes.html
- https://github.com/checkstyle/checkstyle/releases/tag/checkstyle-10.12.0
- checkstyle/checkstyle@checkstyle-10.11.0...checkstyle-10.12.0

pom.xml

@@ -839,7 +839,7 @@
                         <dependency>
                             <groupId>com.puppycrawl.tools</groupId>
                             <artifactId>checkstyle</artifactId>
-                            <version>10.11.0</version>
+                            <version>10.12.0</version>
                         </dependency>
                         <dependency>
                             <groupId>io.spring.nohttp</groupId>