feat(nix/buildkite): add meta.ci.buildkiteExtraDeps r/6442

This allows setting a buildkiteExtraDeps in `meta.ci`, which will get
added to `depends_on` (which can also be a list).

It allows explicitly describing a dependency on another buildkite step,
either generated by nix/buildkite, or part of the static pipeline.

At some point we might want to expose our key calculation function too,
similar to how readTree exposes mkLabel already, but that's left for
a followup.

Change-Id: I793170401ccd3907ad8bf232b80ca7a492e1c942
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8980
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

0 files changed, 0 insertions, 0 deletions