fix(ci): download release assets from release_build step before calling release.sh (#83)

The release step gets a fresh workspace — neither builddeck,
builddeck.sha256, nor builddeck.tag survive from the previous step.
Download all three from --step release_build before invoking
release.sh so the GitHub release has real assets to upload.

Same fix for pipeline.release.yml: download from --step build.

Author: alexhraber

.buildkite/pipeline.release.yml

@@ -19,6 +19,9 @@ steps:
   - label: ":rocket: GitHub Release"
     key: release
     depends_on: build
-    command: .buildkite/release.sh "${BUILDKITE_TAG}"
+    command: |
+      buildkite-agent artifact download builddeck . --step build
+      buildkite-agent artifact download builddeck.sha256 . --step build
+      .buildkite/release.sh "${BUILDKITE_TAG}"
     secrets:
       - GITHUB_TOKEN

.buildkite/pipeline.yml

@@ -117,6 +117,8 @@ steps:
     command: |
       if buildkite-agent artifact download builddeck.tag . --step release_build 2>/dev/null && [[ -s builddeck.tag ]]; then
         VERSION=$(cat builddeck.tag)
+        buildkite-agent artifact download builddeck . --step release_build
+        buildkite-agent artifact download builddeck.sha256 . --step release_build
         echo "Creating GitHub release for ${VERSION}"
         .buildkite/release.sh "${VERSION}"
       else