Merge pull request #28 from neziw/renovate/checkstyle-13.x

Update dependency checkstyle to v13

Author: neziw

build.gradle

@@ -15,7 +15,7 @@ java {
 }
 
 checkstyle {
-    toolVersion = "12.3.1"
+    toolVersion = "13.3.0"
     maxWarnings = 0
 }