fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-COMTHOUGHTWORKSXSTREAM-8352924

pom.xml

@@ -356,7 +356,7 @@
 			<dependency>
 				<groupId>com.thoughtworks.xstream</groupId>
 				<artifactId>xstream</artifactId>
-				<version>1.4.17</version>
+				<version>1.4.21</version>
 			</dependency>
 			<dependency>
 				<groupId>javax.mail</groupId>
@@ -1057,9 +1057,9 @@
 				<version>3.4.0</version>
 				<configuration>
 					<docfilessubdirs>true</docfilessubdirs>
-					<bottom>&lt;em>&lt;small> Generated ${TIMESTAMP} NOTE - these libraries are in active development and subject to change&lt;/small>&lt;/em></bottom>
-					<header>&lt;a href="https://www.openmrs.org" target=_top>&lt;img src="resources/openmrs-logo-small.gif" border=0/>&lt;/a></header>
-					<footer>&lt;a href="https://www.openmrs.org" target=_top>${project.name}&lt;/a></footer>
+					<bottom>&lt;em&gt;&lt;small&gt; Generated ${TIMESTAMP} NOTE - these libraries are in active development and subject to change&lt;/small&gt;&lt;/em&gt;</bottom>
+					<header>&lt;a href="https://www.openmrs.org" target=_top&gt;&lt;img src="resources/openmrs-logo-small.gif" border=0/&gt;&lt;/a&gt;</header>
+					<footer>&lt;a href="https://www.openmrs.org" target=_top&gt;${project.name}&lt;/a&gt;</footer>
 				</configuration>
 			</plugin>
 			<plugin>