Bump fast-xml-parser from 5.5.6 to 5.5.7 in /docs

Bumps [fast-xml-parser](https://github.com/NaturalIntelligence/fast-xml-parser) from 5.5.6 to 5.5.7.
- [Release notes](https://github.com/NaturalIntelligence/fast-xml-parser/releases)
- [Changelog](https://github.com/NaturalIntelligence/fast-xml-parser/blob/master/CHANGELOG.md)
- [Commits](NaturalIntelligence/fast-xml-parser@v5.5.6...v5.5.7)

---
updated-dependencies:
- dependency-name: fast-xml-parser
  dependency-version: 5.5.7
  dependency-type: direct:development
...

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

Author: dependabot[bot]

docs/package-lock.json

@@ -18,7 +18,7 @@
     "nhsuk-frontend": "^10.1.0"
   },
   "devDependencies": {
-    "fast-xml-parser": "^5.5.6",
+    "fast-xml-parser": "^5.5.7",
     "pa11y-ci": "^3.1.0",
     "pa11y-ci-reporter-html": "^6.0.2",
     "pm2": "^5.4.1",