Bump undertowVersion from 2.2.38.Final to 2.3.26.Final

Bumps `undertowVersion` from 2.2.38.Final to 2.3.26.Final.

Updates `io.undertow:undertow-core` from 2.2.38.Final to 2.3.26.Final
- [Release notes](https://github.com/undertow-io/undertow/releases)
- [Commits](undertow-io/undertow@2.2.38.Final...2.3.26.Final)

Updates `io.undertow:undertow-servlet` from 2.2.38.Final to 2.3.26.Final
- [Release notes](https://github.com/undertow-io/undertow/releases)
- [Commits](undertow-io/undertow@2.2.38.Final...2.3.26.Final)

---
updated-dependencies:
- dependency-name: io.undertow:undertow-core
  dependency-version: 2.3.26.Final
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.undertow:undertow-servlet
  dependency-version: 2.3.26.Final
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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>2.2.38.Final</undertowVersion>
+    <undertowVersion>2.3.26.Final</undertowVersion>
     <slf4j.versoin>1.7.36</slf4j.versoin>
   </properties>