Bump org.htmlunit:htmlunit (#117)

Bumps the gradle-dependencies group in /functional-tests with 1 update: [org.htmlunit:htmlunit](https://github.com/HtmlUnit/htmlunit).


Updates `org.htmlunit:htmlunit` from 4.16.0 to 4.18.0
- [Release notes](https://github.com/HtmlUnit/htmlunit/releases)
- [Commits](HtmlUnit/htmlunit@4.16.0...4.18.0)

---
updated-dependencies:
- dependency-name: org.htmlunit:htmlunit
  dependency-version: 4.18.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: gradle-dependencies
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

functional-tests/build.gradle

@@ -11,7 +11,7 @@ repositories {
 dependencies {
     testImplementation 'junit:junit:4.13.2'
     testImplementation 'com.thoughtworks.gauge:gauge-java:+'
-    testImplementation 'org.htmlunit:htmlunit:4.16.0'
+    testImplementation 'org.htmlunit:htmlunit:4.18.0'
     testImplementation 'se.fishtank:css-selectors:2.0'
     testImplementation 'org.jsoup:jsoup:1.21.2'
     testImplementation 'org.assertj:assertj-core:3.27.6'