Bump io.undertow:undertow-core from 2.3.19.Final to 2.3.20.Final

Bumps [io.undertow:undertow-core](https://github.com/undertow-io/undertow) from 2.3.19.Final to 2.3.20.Final.
- [Release notes](https://github.com/undertow-io/undertow/releases)
- [Commits](undertow-io/undertow@2.3.19.Final...2.3.20.Final)

---
updated-dependencies:
- dependency-name: io.undertow:undertow-core
  dependency-version: 2.3.20.Final
  dependency-type: direct:production
...

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

Author: dependabot[bot]

pom.xml

@@ -42,7 +42,7 @@
     <projectOwner>Red Hat, Inc.</projectOwner>
     <projectEmail>https://github.com/Commonjava/http-testserver</projectEmail>
     <javaVersion>11</javaVersion>
-    <undertowVersion>2.3.19.Final</undertowVersion>
+    <undertowVersion>2.3.20.Final</undertowVersion>
     <quarkus.version>3.6.9</quarkus.version>
   </properties>