Bump org.eclipse.jetty:jetty-bom from 10.0.18 to 10.0.20 (#538)

Bumps [org.eclipse.jetty:jetty-bom](https://github.com/jetty/jetty.project) from 10.0.18 to 10.0.20.
- [Release notes](https://github.com/jetty/jetty.project/releases)
- [Commits](jetty/jetty.project@jetty-10.0.18...jetty-10.0.20)

---
updated-dependencies:
- dependency-name: org.eclipse.jetty:jetty-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pom.xml

@@ -44,7 +44,7 @@
   <properties>
     <changelist>999999-SNAPSHOT</changelist>
     <scmTag>HEAD</scmTag>
-    <jetty.version>10.0.18</jetty.version>
+    <jetty.version>10.0.20</jetty.version>
     <gitHubRepo>jenkinsci/stapler</gitHubRepo>
   </properties>