ci: read FC trigger url from variables

Author: gujieye

.github/workflows/publish-skills.yml

@@ -24,4 +24,4 @@ jobs:
     steps:
       - name: Trigger FC publish-skills
         run: |
-          curl -sf -X POST "${{ secrets.FC_TRIGGER_URL }}/publish-skills?repo=modelstudioai/cli&branch=${{ github.ref_name }}"
+          curl -sf -X POST "${{ vars.FC_TRIGGER_URL }}/publish-skills?repo=modelstudioai/cli&branch=${{ github.ref_name }}"