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] <[email protected]>

.github/workflows/ci-locks.yml

@@ -107,7 +107,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: "Download lock artifacts"
-      uses: actions/download-artifact@v3
+      uses: actions/download-artifact@v4
       with:
         name: lock-artifacts
         path: ${{ github.workspace }}/requirements/locks

.github/workflows/ci-wheels.yml

@@ -102,7 +102,7 @@ jobs:
     name: "Show artifacts"
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/download-artifact@v3
+    - uses: actions/download-artifact@v4
       with:
         name: pypi-artifacts
         path: ${{ github.workspace }}/dist
@@ -119,7 +119,7 @@ jobs:
     # upload to Test PyPI for every commit on main branch
     if: github.event_name == 'push' && github.event.ref == 'refs/heads/main'
     steps:
-    - uses: actions/download-artifact@v3
+    - uses: actions/download-artifact@v4
       with:
         name: pypi-artifacts
         path: ${{ github.workspace }}/dist
@@ -140,7 +140,7 @@ jobs:
     # upload to PyPI for every tag starting with 'v'
     if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/v')
     steps:
-    - uses: actions/download-artifact@v3
+    - uses: actions/download-artifact@v4
       with:
         name: pypi-artifacts
         path: ${{ github.workspace }}/dist