Bump checkstyle from 8.30 to 8.31 (#6215)

Bumps [checkstyle](https://github.com/checkstyle/checkstyle) from 8.30 to 8.31.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](checkstyle/checkstyle@checkstyle-8.30...checkstyle-8.31)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

build.gradle

@@ -212,7 +212,7 @@ dependencies {
     testImplementation "org.testfx:testfx-junit5:4.0.17-alpha-SNAPSHOT"
     testImplementation "org.hamcrest:hamcrest-library:2.2"
 
-    checkstyle 'com.puppycrawl.tools:checkstyle:8.30'
+    checkstyle 'com.puppycrawl.tools:checkstyle:8.31'
     xjc group: 'org.glassfish.jaxb', name: 'jaxb-xjc', version: '2.3.2'
     jython 'org.python:jython-standalone:2.7.1'
 }