Upgrade checkstyle to 8.13

Author: jsotuyod

CHANGELOG.md

@@ -6,6 +6,7 @@
 Improvements:
  * Upgraded to Gradle 4.10.2
  * Upgraded PMD to 6.8.0
+ * Upgraded Checkstyle to 8.13
  * All lint tasks (ie: lintDebug and lintRelease) are now cacheable and can be up-to-date
 
 ### 2.6.8

src/main/groovy/com/monits/gradle/sca/ToolVersions.groovy

@@ -26,7 +26,7 @@ final class ToolVersions {
     private final static String BACKWARDS_PMD_TOOL_VERSION = '5.1.3'
     private final static GradleVersion GRADLE_VERSION_PMD = GradleVersion.version('2.4')
 
-    private final static String LATEST_CHECKSTYLE_VERSION = '8.12'
+    private final static String LATEST_CHECKSTYLE_VERSION = '8.13'
     private final static String LATEST_CHECKSTYLE_VERSION_JAVA_7 = '6.19'
     private final static String BACKWARDS_CHECKSTYLE_VERSION = '6.7'
     private final static GradleVersion GRADLE_VERSION_CHECKSTYLE = GradleVersion.version('2.7')