Bump xstream from 1.4.11.1 to 1.4.15

Bumps [xstream](https://github.com/x-stream/xstream) from 1.4.11.1 to 1.4.15.
- [Release notes](https://github.com/x-stream/xstream/releases)
- [Commits](https://github.com/x-stream/xstream/commits)

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -88,7 +88,7 @@
 		<dependency>
 			<groupId>com.thoughtworks.xstream</groupId>
 			<artifactId>xstream</artifactId>
-			<version>1.4.11.1</version>
+			<version>1.4.15</version>
 			<scope>provided</scope>
 		</dependency>
 		<dependency>