Update contributing instructions

[BenSpencer]

Hey, I wanted to update the package to include some new icons (or their new names), which I have done in #2

But I found the contributing instructions hard to follow, lots of the info in the template doesn't seem to match this project. I wasn't sure what direction you might want to switch (e.g. eslint vs prettier vs whatever) so I haven't made any changes directly.

The parts I spotted:

• Are the npm/node versions right? I had npm 6.x on my machine and this rewrote the entirety of package-lock.json to use lockfileVersion:1. Switching to the latest (9.x) resolved it, and I didn't dig into exactlly what version is expected.
• In step 3 it says npm where I assume it means npm install?
• Step 4 doesn't seem relevant at all
• I wasn't clear if the tip was actually wanted?
• Under the PR submission instructions it says to run the tests, but there are no tests.
• It also says to run npm run lint but that command doesn't work. It's defined as eslint src but needs to be something like eslint src/**/*.ts. But switching to that just makes eslint complain that there's no config file.
• I could run prettier OK with npx prettier -w src in case that's useful to include.

[naquiroz]

Thanks for the suggestions! Yes, I was in a bit of a hurry when I did the contribution guide, I'll have a look at it and edit it. Would you mind reviewing it after I make a PR?

[BenSpencer]

Happily! I can also help, I just wasn't sure which direction you'd prefer so I didn't just make up something entirely different myself 🙃

[naquiroz]

Sorry about this, do you still need me to push it? I plan to put this package back on track

[BenSpencer]

I'm still happy to review if useful, but it's not blocking for the work I was doing. 👍

[naquiroz]

Hi, apologies for the very long wait. V2 released!

[naquiroz]

Documentation needs rework, feel free to contribute