Upgrade tomcat 8.5.21

Author: slandelle

Diff for: pom.xml

@@ -391,7 +391,7 @@
 		<logback.version>1.2.3</logback.version>
 		<testng.version>6.11</testng.version>
 		<jetty.version>9.4.7.v20170914</jetty.version>
-		<tomcat.version>8.5.20</tomcat.version>
+		<tomcat.version>8.5.21</tomcat.version>
 		<commons-io.version>2.5</commons-io.version>
 		<commons-fileupload.version>1.3.3</commons-fileupload.version>
 		<privilegedaccessor.version>1.2.2</privilegedaccessor.version>