Bump org.htmlunit:htmlunit from 3.11.0 to 4.0.0

Bumps [org.htmlunit:htmlunit](https://github.com/HtmlUnit/htmlunit) from 3.11.0 to 4.0.0.
- [Release notes](https://github.com/HtmlUnit/htmlunit/releases)
- [Commits](HtmlUnit/htmlunit@3.11.0...4.0.0)

---
updated-dependencies:
- dependency-name: org.htmlunit:htmlunit
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

This closes #143

doxia-site-renderer/pom.xml

@@ -172,7 +172,7 @@ under the License.
     <dependency>
       <groupId>org.htmlunit</groupId>
       <artifactId>htmlunit</artifactId>
-      <version>3.11.0</version>
+      <version>4.0.0</version>
       <scope>test</scope>
       <exclusions>
         <exclusion>