[Hotfix] 2.7.2 Add missing @babel dependency

[bendvc]

This PR is a hotfix to add a missing dependency in pwa-kit-dev which causes any generated project not to start. We are also bumping the version to 2.7.2-preview.0.

If all goes well there will be a follow up PR to bump to 2.7.2

To test this generate a project using the following commands

// clear npx cache
> rm -rf ~/.npm/_npx
// generate project using demo instance
> node packages/pwa-kit-create-app/scripts/create-mobify-app-dev.js --outputDir generated-project
// move to generated project and start
> cd generate-project && npm start