KNOX-2328 - Upgrade checkstyle to 8.31

Signed-off-by: Kevin Risden <krisden@apache.org>
diff --git a/pom.xml b/pom.xml
index d28b7ba..34b26c0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -161,7 +161,7 @@
         <ben-manes.caffeine.version>2.8.1</ben-manes.caffeine.version>
         <buildnumber-maven-plugin.version>1.4</buildnumber-maven-plugin.version>
         <cglib.version>3.3.0</cglib.version>
-        <checkstyle.version>8.30</checkstyle.version>
+        <checkstyle.version>8.31</checkstyle.version>
         <cloudera-manager.version>7.0.3</cloudera-manager.version>
         <cloudera-manager-api-swagger.version>${cloudera-manager.version}</cloudera-manager-api-swagger.version>
         <commons-beanutils.version>1.9.4</commons-beanutils.version>