Bump xstream from 1.4.6 to 1.4.15 in /jodconverter-web

Bumps [xstream](https://github.com/x-stream/xstream) from 1.4.6 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>

jodconverter-web/pom.xml

@@ -158,7 +158,7 @@
         <dependency>
             <groupId>com.thoughtworks.xstream</groupId>
             <artifactId>xstream</artifactId>
-            <version>1.4.6</version>
+            <version>1.4.15</version>
         </dependency>
         <dependency>
             <groupId>com.google.guava</groupId>