A small script that parses `nix-instantiate -vv` output to track the
files read while instantiating a depot build.
Change-Id: I5acf31d55f39c1d1acf9cdead03d33e2c8abab6a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1646
Reviewed-by: edef <edef@edef.eu>
Tested-by: BuildkiteCI