Bump checkstyle and Maven checkstyle versions.

Author: michael-simons

pom.xml

@@ -86,12 +86,12 @@
 
 	<properties>
 		<changelist>-SNAPSHOT</changelist>
-		<checkstyle.version>8.18</checkstyle.version>
+		<checkstyle.version>8.29</checkstyle.version>
 		<flatten-maven-plugin.version>1.1.0</flatten-maven-plugin.version>
 		<jacoco-maven-plugin.version>0.8.5</jacoco-maven-plugin.version>
 		<java.version>1.8</java.version>
 		<maven.version>3.6.1</maven.version>
-		<maven-checkstyle-plugin.version>3.0.0</maven-checkstyle-plugin.version>
+		<maven-checkstyle-plugin.version>3.1.0</maven-checkstyle-plugin.version>
 		<maven-deploy-plugin.version>3.0.0-M1</maven-deploy-plugin.version>
 		<maven-enforcer-plugin.version>3.0.0-M2</maven-enforcer-plugin.version>
 		<maven-failsafe-plugin.version>3.0.0-M4</maven-failsafe-plugin.version>