Bump org.jenkins-ci.plugins:email-ext in /.ci/jenkins/tests

Bumps [org.jenkins-ci.plugins:email-ext](https://github.com/jenkinsci/email-ext-plugin) from 2.66 to 2.96.1.
- [Release notes](https://github.com/jenkinsci/email-ext-plugin/releases)
- [Changelog](https://github.com/jenkinsci/email-ext-plugin/blob/master/CHANGELOG.adoc)
- [Commits](jenkinsci/email-ext-plugin@email-ext-2.66...email-ext-2.96.1)

---
updated-dependencies:
- dependency-name: org.jenkins-ci.plugins:email-ext
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

.ci/jenkins/tests/pom.xml

@@ -211,7 +211,7 @@
             <!-- provides emailText() step -->
             <groupId>org.jenkins-ci.plugins</groupId>
             <artifactId>email-ext</artifactId>
-            <version>2.66</version>
+            <version>2.96.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>