CI: use hashes for download-artifact and github-pages-deploy

Author: ev-br

.github/workflows/docs.yml

@@ -47,12 +47,12 @@ jobs:
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Download Artifact
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093  # v4.3.0
         with:
           name: docs-build
           path: docs/build/
 
       - name: Deploy to GitHub pages
-        uses: JamesIves/github-pages-deploy-action@v4
+        uses: JamesIves/github-pages-deploy-action@6c2d9db40f9296374acc17b90404b6e8864128c8  # v4.7.3
         with:
           folder: docs/build/