Update Arch Linux package link

[dumbasPL]

The community repository was merged into extra during the Arch Linux Git migration and no longer exists

PS: I've noticed there is a package for nebula in Alpine Linux, Wouldn't it be a good idea to add it to the list as well?

[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @dumbasPL to sign the Salesforce Inc. Contributor License Agreement.

[nbrownus]

Thanks for the update!

PS: I've noticed there is a package for nebula in Alpine Linux, Wouldn't it be a good idea to add it to the list as well?

Certainly, do you mind adding it to the PR?

[dumbasPL]

Sorry for the delay, I forgot about this PR. I've also added a Debian link since that's a popular server distro.

Note about Alpine: unfortunately, they don't have a nice "stable" link. The current one without a branch specified points to the edge branch. The only potential problem with this is that users might get confused about the version available without noticing that they are looking at the edge (testing) branch. Since Alpine isn't a rolling release distro, the stable version will sometimes be a few versions behind. The alternative would be to put a link the the current stable branch but that also means that it will need to be updated every time Alpine releases a new version.