Release v3.14.0 of GOV.UK Frontend to npm 🚀

[vanitabarrett]

Release GOV.UK Frontend v3.14.0 following the support-branch release process

Done when:

This will be done when:

• decide which release process we're following (usual release process vs trialling the support-branch release process)
• the package has been published on npm
• the release has been created on GitHub
• the release has been communicated via our comms channels
• the sprint board has been updated
• tidy up the milestone

[vanitabarrett]

We've decided to try and follow the support branch release process for this release. It’s a bit of an artificial situation because we probably wouldn’t normally 1) not actually have any breaking changes on main, 2) already have merged these changes into main and 3) do a feature release from a support branch. But doing this work will hopefully give us the confidence to merge breaking changes into main knowing that we have a strategy if any high priority fixes pop up.