Bump actions/download-artifact from 4.1.8 to 4.2.1

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4.1.8 to 4.2.1.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4.1.8...v4.2.1)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/on_call_staging_test.yaml

@@ -8,7 +8,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Fetch site artifact
-        uses: actions/download-artifact@v4.1.8
+        uses: actions/download-artifact@v4.2.1
         with:
           name: _site
       - name: extract site artifact

.github/workflows/on_push_to_master_test_and_deploy.yaml

@@ -23,14 +23,14 @@ jobs:
     needs: staging_test
     steps:
       - name: Fetch site artifact
-        uses: actions/download-artifact@v4.1.8
+        uses: actions/download-artifact@v4.2.1
         with:
           name: _site
       - name: extract site artifact
         run: |
           tar -xzf _site.tar.gz
       - name: Fetch httpd conf artifact
-        uses: actions/download-artifact@v4.1.8
+        uses: actions/download-artifact@v4.2.1
         with:
           name: httpd.conf
           path: _drafts/staging/httpd.conf