chore(deps): bump jetty-servlets in /client/stub-server

Bumps [jetty-servlets](https://github.com/eclipse/jetty.project) from 9.0.3.v20130506 to 9.4.41.v20210516.
- [Release notes](https://github.com/eclipse/jetty.project/releases)
- [Commits](jetty/jetty.project@jetty-9.0.3.v20130506...jetty-9.4.41.v20210516)

---
updated-dependencies:
- dependency-name: org.eclipse.jetty:jetty-servlets
  dependency-type: direct:production
...

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

client/stub-server/pom.xml

@@ -19,7 +19,7 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <jetty.version>9.0.3.v20130506</jetty.version>
+    <jetty.version>9.4.41.v20210516</jetty.version>
   </properties>
   <dependencies>
     <dependency>