pipeline: add exec

The current version uses `exec` instead of running this as a script.

Change-Id: Iba99753ba556b1713e73255de49b4a5c54867cd5
Signed-off-by: Raito Bezarius <raito@lix.systems>

static-pipeline.yaml

@@ -1,3 +1,4 @@
+---
 # buildkite static setup file, in case the pipeline gets lost
 
 steps:
@@ -6,4 +7,4 @@ steps:
       queue: "x86_64-linux"
       large: true
     command: |
-      nix --tarball-ttl 0 run "git+$${BUILDKITE_REPO}?ref=refs/heads/ci-config"
+      exec nix --tarball-ttl 0 run "git+$${BUILDKITE_REPO}?ref=refs/heads/ci-config"