Publish a -beta.2 pre-release with the latest round of fixes

[romaricpascal]

What

Run a new pre-release for -beta.2 that includes the fixes we've done so far

Why

Allow people to test the fixed UMD modules, as well as remind of the pre-release to give a chance for late feedback.

Who needs to work on this

Developers, Tech writers (for the changelog)

Who needs to review this

Developers, Tech writers

Done when

• We've added changelog entries for the added fixes
• We've published a new pre-release
• We've announced the new pre-release where we announced the initial one
• We've updated the Design System preview to use the new pre-release
• We've updated the GOV.UK Frontend docs to use the new pre-release

[romaricpascal]

All done 🥳

• https://github.com/alphagov/govuk-frontend/releases/tag/v5.0.0-beta.2
• https://www.npmjs.com/package/govuk-frontend/v/5.0.0-beta.2