Merge pull request #5 from neziw/renovate/checkstyle-10.x

Update dependency checkstyle to v10.20.0

build.gradle.kts

@@ -20,7 +20,7 @@ java {
 }
 
 checkstyle {
-    toolVersion = "10.18.2"
+    toolVersion = "10.20.0"
     maxWarnings = 0
 }