Bump wagtail from 2.16.2 to 4.2.2

Bumps [wagtail](https://github.com/wagtail/wagtail) from 2.16.2 to 4.2.2.
- [Release notes](https://github.com/wagtail/wagtail/releases)
- [Changelog](https://github.com/wagtail/wagtail/blob/main/CHANGELOG.txt)
- [Commits](wagtail/wagtail@v2.16.2...v4.2.2)

---
updated-dependencies:
- dependency-name: wagtail
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 
 Django[argon2]==3.2.17
-wagtail==2.16.2
+wagtail==4.2.2
 
 # External Libraries
 requests==2.28.2