feat(sec): harden GHA ref by using its SHA ID to prevent accidental usage of compromised actions (#38782)

Signed-off-by: hainenber <dotronghai96@gmail.com>
(cherry picked from commit 83823911b5)

.github/workflows/showtime-trigger.yml

@@ -37,7 +37,7 @@ jobs:
     steps:
       - name: Security Check - Authorize Maintainers Only
         id: auth
-        uses: actions/github-script@v8
+        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
@@ -147,7 +147,7 @@ jobs:
 
       - name: Checkout PR code (only if build needed)
         if: steps.auth.outputs.authorized == 'true' && steps.check.outputs.build_needed == 'true'
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           ref: ${{ steps.check.outputs.target_sha }}
           persist-credentials: false