build providers.json with JS

[zemlanin]

this will allow to install the package from github (via npm install iamcal/oembed), in addition to (infrequently updated) npm

[iamcal]

why would you want to install the package? (genuinely curious!)

[zemlanin]

I have a custom made blog engine/generator, which, among other things, renders preview "cards" based opengraph and oembed data. When the previewed url doesn't have related <meta> tags, I'm using this package as a fallback

List of providers in this repo is updated quite often, unlike the npm package. While choosing between these options:

• automate publishing someone else's package, while not having an access to the package's npm;
• hardcode providers.json in the generator's repo and remember to update it;
• from time to time, check this repo for updates and remind maintainers to npm publish;
• make "nightly" providers.json installable from the git (it would still be publishable and installable the old way)

I choose the last one, as a combination of "not too hard", "not too manual", and "not too bothersome for the maintainers"

[iamcal]

thank you for the explanation - makes a lot of sense.

i've merged your changes and updated the README to explain how to use the repo as an NPM package