Add a Discord announcement about the npm min-release-age config

[goran1010]

As seen in this PR, we've recently added the config which when set up, delays installation of packages by 3 days.

This is meant to give a decent amount of protection to the learners from attacks similar to the recent axios attack.

Now, I'd like to propose making an announcement in our Discord server, to let other learners know about his config - since right now, only new learners going through this lesson will be aware of it, and potentially reap its benefits.

We don't have to tag everyone, since this isn't a time sensitive issue (that much), just making it a regular announcement should suffice.

[mao-sz]

Didn't see this but sorted anyway