Talk: Flakes

A lot of the attributes listed in the schema are out of date.

Using flakes with NixOS

looks like upgrading NixOS when using flakes now requires

``` $ nixos-rebuild switch --upgrade --recreate-lock-file ```

I noticed that a lot of people complain that flakes are hard to understand. The first paragraph of this article used to be very confusing and didn't really capture what I feel flakes are truly about. I've rewritten it to be more direct about the local locking of dependencies, which is what I see as the truly essential flake feature. -- User:Sid-code