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>

Author: dependabot[bot]

pom.xml

@@ -61,7 +61,7 @@
         <reflections.version>0.9.10</reflections.version>
         <jersey-bean-validation.version>2.21</jersey-bean-validation.version>
         <aspectj.version>1.9.5</aspectj.version>
-        <xstream.version>1.4.15</xstream.version>
+        <xstream.version>1.4.19</xstream.version>
         <jersey.version>2.16</jersey.version>
         <junit.version>4.13.1</junit.version>
         <mysql.version>5.1.49</mysql.version>