Docs not building on netlify

[sfreytag]

I opened a PR with some minor content changes to one page and the docs did not build, with a couple of errors reported from Netlify.

Based on the vuejs/docs repo and internet advice, the fixes required are:

• Simplify the netflix.toml file
• Add a preinstall command
• Update the lockfile from a local install

I've done this in my PR #54 to get it to build, but I thought it might be better as a separate PR so that the build changes are not conflated with the doc changes.