ci: update reusable-promote.yml to merged SHA 8487dff # v1

Replaces branch SHA (c677c2f) with the merged actions main SHA.
No functional change — same workflow, now pinned to @v1 equivalent.

Assisted-by: Claude Sonnet 4.5 via pi

Author: castrojo

.github/workflows/promote-testing-to-main.yml

@@ -20,7 +20,7 @@ permissions:
 
 jobs:
   promote:
-    uses: projectbluefin/actions/.github/workflows/reusable-promote.yml@c677c2fe5d5efe8118c1dcabd481cec3cde924f7
+    uses: projectbluefin/actions/.github/workflows/reusable-promote.yml@8487dff61267ca80486164379fcfc21901d2021e # v1
     with:
       variants: '["dakota","dakota-nvidia"]'
       cosign_identity_regexp: >-