Bump checkstyle from 8.22 to 8.23 (#5153)

Bumps [checkstyle](https://github.com/checkstyle/checkstyle) from 8.22 to 8.23.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](checkstyle/checkstyle@checkstyle-8.22...checkstyle-8.23)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build.gradle

@@ -173,7 +173,7 @@ dependencies {
     testCompile "org.testfx:testfx-core:4.0.+"
     testCompile "org.testfx:testfx-junit5:4.0.+"
 
-    checkstyle 'com.puppycrawl.tools:checkstyle:8.22'
+    checkstyle 'com.puppycrawl.tools:checkstyle:8.23'
     xjc 'com.sun.xml.bind:jaxb-xjc:2.2.4-1'
     jython 'org.python:jython-standalone:2.7.1'
 }