Add pino-discord-webhook transport information

[fabulousgk]

This PR adds a discord webhook transport to the list of known transports.

[mcollina]

Can you please add a few tests?
How could someone get the webhook url? Are there security tokens involved?

[fabulousgk]

I added information about how to create a webhook and get the URL.

I have tried adding testing, but I have no experience with test suites in JS. I looked at the Slack one, but my setup is a bit different.

The main issue is I am not sure how to test the actual sending as that is wrapped in the callback function.

So I can test that the transport is created, but nothing beyond that. If someone gives me hints I will add it.

I will alos ask elsewere.

I noticed that there are transports without tests, is this required for publising?

[mcollina]

I noticed that there are transports without tests, is this required for publising?

I double checked and only the logtail one does not have tests. This is unfortunate and it slipped.

Overally, yes, I consider tests to be a requirement for inclusion in this list.

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To test this I would spin up an http server and pass its URL as the webhook. Then, verify this endpoint is called with the expected output.

[fabulousgk]

Well, I added a test. The idea of a webserver seemed not impossible since what I am doing is simply calling a class in the discord.js library, which handles the rest of the interaction. So I am testing that that call occurs.

[mcollina]

lgtm