Add @babel/runtime dev dependency

[andygout]

When bower linking from this component to next-front-page and then running make build (on next-front-page) I encountered this error:

Which presents itself again in the client-side console:

An investigation suggested that I install babel-runtime as a dev dependency, which has resolved the issue and enabled me to run next-front-page locally whilst bower linking to a local instance of n-syndication.

References:

• GitHub wojtekmaj/react-pdf - Issues: "Module not found: Error: Can't resolve 'babel-runtime/regenerator'".

New dev dependencies:

• npm: @babel/runtime.
• Babel: @babel/runtime.