fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-IOUNDERTOW-15053841
- https://snyk.io/vuln/SNYK-JAVA-IOUNDERTOW-14908846

Author: snyk-io[bot]

pom.xml

@@ -43,7 +43,7 @@
 	<dependency>
 		<groupId>io.undertow</groupId>
 		<artifactId>undertow-core</artifactId>
-		<version>2.0.9.Final</version>
+		<version>2.3.21.Final</version>
 	</dependency>
 	<dependency>
     <groupId>javax.servlet</groupId>