Bump xstream from 1.4.15 to 1.4.19

Bumps [xstream](https://github.com/x-stream/xstream) from 1.4.15 to 1.4.19.
- [Release notes](https://github.com/x-stream/xstream/releases)
- [Commits](https://github.com/x-stream/xstream/commits)

---
updated-dependencies:
- dependency-name: com.thoughtworks.xstream:xstream
  dependency-type: direct:production
...

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

pom.xml

@@ -166,7 +166,7 @@
 				<dependency>
 					<groupId>com.thoughtworks.xstream</groupId>
 					<artifactId>xstream</artifactId>
-					<version>1.4.15</version> <!-- apparently this needs to be exactly this version -->
+					<version>1.4.19</version> <!-- apparently this needs to be exactly this version -->
 				</dependency>
 			</dependencies>
 			</plugin>