fix: docker image not building

[felipecrs]

The docker image is not currently building, it just gets stuck forever.

I think it's because of some npm scripts.

So, first I updated all dependencies within ranges with npm update --save, and then I updated puppeteer and sharp to their latest versions.

Also, I took this opportunity to modernize the Dockerfile and make it much quicker to build.

Note I removed licensed, but I plan to bring it back once pkgxdev/pantry#9488 is completed. EDIT: done.

[felipecrs]

Just in case someone else needs this before @lowlighter gets around to merging it, you can use my fork:

- uses: felipecrs/metrics@master
  with:
    use_prebuilt_image: no

[mikey-]

Great work! Like I said before, I have absolutely no sway here - but I've taken a look and approved the changes anyway :)