build(deps): Bump the production-dependencies group across 1 directory with 2 updates

Bumps the production-dependencies group with 2 updates in the / directory: [@x-govuk/govuk-eleventy-plugin](https://github.com/x-govuk/govuk-eleventy-plugin) and [govuk-frontend](https://github.com/alphagov/govuk-frontend/tree/HEAD/packages/govuk-frontend).


Updates `@x-govuk/govuk-eleventy-plugin` from 8.3.0 to 8.3.1
- [Release notes](https://github.com/x-govuk/govuk-eleventy-plugin/releases)
- [Commits](x-govuk/govuk-eleventy-plugin@v8.3.0...v8.3.1)

Updates `govuk-frontend` from 5.14.0 to 6.0.0
- [Release notes](https://github.com/alphagov/govuk-frontend/releases)
- [Changelog](https://github.com/alphagov/govuk-frontend/blob/main/CHANGELOG.md)
- [Commits](https://github.com/alphagov/govuk-frontend/commits/v6.0.0/packages/govuk-frontend)

---
updated-dependencies:
- dependency-name: "@x-govuk/govuk-eleventy-plugin"
  dependency-version: 8.3.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: production-dependencies
- dependency-name: govuk-frontend
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: production-dependencies
...

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

Author: dependabot[bot]

package-lock.json

@@ -32,8 +32,8 @@
   "license": "MIT",
   "dependencies": {
     "@sindresorhus/slugify": "^3.0.0",
-    "@x-govuk/govuk-eleventy-plugin": "^8.3.0",
-    "govuk-frontend": "5.14.0",
+    "@x-govuk/govuk-eleventy-plugin": "^8.3.1",
+    "govuk-frontend": "6.0.0",
     "jspdf": "^4.2.0",
     "markdown-it": "^14.1.1"
   },