There's no need for us to reinvent the wheel here.
niv pins are in //third_party/sources, and niv commands need to be run
with `niv -s third_party/sources/sources.json` to operate on the
correct file.
Note that niv by default wants to put the loader file in
//nix/sources.nix. This file has been moved to
//third_party/sources/default.nix which makes niv throw a warning, but
everything still works as intended.
Change-Id: I2b2a6f8edf33c429a6d7be9d174ba1996d9a0193
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5143
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
