Build(deps): bump plek from 5.2.2 to 5.3.0

Bumps [plek](https://github.com/alphagov/plek) from 5.2.2 to 5.3.0.
- [Changelog](https://github.com/alphagov/plek/blob/main/CHANGELOG.md)
- [Commits](alphagov/plek@v5.2.2...v5.3.0)

---
updated-dependencies:
- dependency-name: plek
  dependency-version: 5.3.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -509,7 +509,7 @@ GEM
       hashery (~> 2.0)
       ruby-rc4
       ttfunk
-    plek (5.2.2)
+    plek (5.3.0)
     pp (0.6.3)
       prettyprint
     prettyprint (0.2.0)