CI: Fix artifacts (upload-artifact@v4)

https://github.com/actions/download-artifact/blob/65a9ed/docs/MIGRATION.md#merging-multiple-artifacts

ref: actions/upload-artifact#478

.github/workflows/build-wheels.yml

@@ -186,7 +186,10 @@ jobs:
 
  - uses: actions/upload-artifact@v4
  with:
- name: wheels
+ # @v4 does not merge artifacts with the name (even if the contents)
+ # are different. So in a matrix, we have to give each artifact a
+ # unique name. We merge these later in another job.
+ name: wheel-${{ matrix.python[0] }}-${{ matrix.buildplat[1] }}
  path: ./wheelhouse/*.whl
 
  build_sdist:
@@ -238,13 +241,25 @@ jobs:
  - name: Upload Source dist
  uses: actions/upload-artifact@v4
  with:
- name: wheels
+ name: sdist
  path: dist
 
+ # Merge all the artifacts into a single bundle
+ # https://github.com/actions/upload-artifact/blob/main/merge/README.md
+ merge-artifacts:
+ runs-on: ubuntu-latest
+ needs: [build_wheels, build_sdist]
+ steps:
+ - name: Merge Artifacts
+ uses: actions/upload-artifact/merge@v4
+ with:
+ name: wheels
+ delete-merged: true
+
  release:
  runs-on: ubuntu-latest
  name: Upload Release to PyPI
- needs: [build_wheels, build_sdist, parse_commit_info]
+ needs: [parse_commit_info, merge-artifacts]
  if: contains(needs.parse_commit_info.outputs.can_release, 'true')
  steps:
  - name: Checkout scikit-misc
@@ -261,7 +276,7 @@ jobs:
  uv pip install --system twine
 
  - name: Download wheels
- uses: actions/download-artifact@v3
+ uses: actions/download-artifact@v4
  with:
  name: wheels
  path: dist
@@ -281,7 +296,7 @@ jobs:
  pre_release:
  runs-on: ubuntu-latest
  name: Upload Release to TestPyPI
- needs: [build_wheels, build_sdist, parse_commit_info]
+ needs: [parse_commit_info, merge-artifacts]
  if: contains(needs.parse_commit_info.outputs.can_pre_release, 'true')
  steps:
  - name: Checkout scikit-misc
@@ -294,7 +309,8 @@ jobs:
 
  - name: Install Release Requirements
  run: |
- pip install -r requirements/release.txt
+ pip install uv
+ uv pip install --system twine
 
  - name: Download wheels
  uses: actions/download-artifact@v3