Upgrade Node and NPM version in Docker

Is there any risk in bumping the Dockerfile node version to 14?

I'm trying to use Backstop in a mono-repo using [npm workspaces](https://docs.npmjs.com/cli/v7/using-npm/workspaces) (new in npm 7). The trick is that the CI Tools I'm using can't call npm commands directly from my root folder, so we instead have to cd to the nested folder and run `npm install`, and `npm run backstop` commands that way. This get's ever more complicated the more things we add to the mono-repo.

```
FROM node:14.17.0
```