updaed Checkstyle version (CVE-2019-9658)

Author: slu-it

pom.xml

@@ -65,7 +65,7 @@
         <version.hamcrest>1.3</version.hamcrest>
         <version.assertj>3.11.1</version.assertj>
         <version.mockito>2.23.0</version.mockito>
-        <version.checkstyle>8.13</version.checkstyle>
+        <version.checkstyle>8.18</version.checkstyle>
 
         <version.jetty-server>9.4.12.v20180830</version.jetty-server>
         <version.okio>1.14.1</version.okio>