node-sass does not build, needs version bump to at least 4.12.0

[jinnatar]

I've run into this issue: sass/libsass#2883 .. bumping the node-sass version to 4.12.0 resolves it.

As a side note, all the deps are horribly out of date:

found 17 vulnerabilities (8 low, 4 moderate, 5 high)
  run `npm audit fix` to fix them, or `npm audit` for details

So yeah, might want to actually update the pins.

[XiMMiX]

Running_the_App_Without_Docker.md instructs to install NodeJS 13. node-sass 4.13.0 is, afaik, the first version to support NodeJS 13, so bumping to that is problably a better idea.
I have just installed openeats using [email protected] and I haven't seen any problems with it yet.