Bump actions/download-artifact from 3 to 4

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v3...v4)

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

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

.github/workflows/build.yml

@@ -293,7 +293,7 @@ jobs:
           python-version: ${{ matrix.python }}
 
       - name: Download cpymad wheels
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: dist-${{ matrix.os }}
           path: dist
@@ -328,7 +328,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: '3.9'
-      - uses: actions/download-artifact@v3
+      - uses: actions/download-artifact@v4
         with:
           name: dist-linux
           path: dist
@@ -362,7 +362,7 @@ jobs:
           python-version: '3.x'
 
       - name: Fetch built distributions
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           path: dist