Bump jenkins-test-harness-htmlunit

Bumps [jenkins-test-harness-htmlunit](https://github.com/jenkinsci/jenkins-test-harness-htmlunit) from 56.vf1eabfc274f8 to 66.v712ea44bccba.
- [Release notes](https://github.com/jenkinsci/jenkins-test-harness-htmlunit/releases)
- [Commits](https://github.com/jenkinsci/jenkins-test-harness-htmlunit/commits)

---
updated-dependencies:
- dependency-name: org.jenkins-ci.main:jenkins-test-harness-htmlunit
  dependency-type: direct:production
...

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

Author: dependabot[bot]

pom.xml

@@ -136,7 +136,7 @@
     <dependency>
       <groupId>org.jenkins-ci.main</groupId>
       <artifactId>jenkins-test-harness-htmlunit</artifactId>
-      <version>56.vf1eabfc274f8</version>
+      <version>66.v712ea44bccba</version>
     </dependency>
     <dependency>
       <groupId>org.jvnet.hudson</groupId>