CI: Rollback for now

There's a migration guide for later
https://github.com/actions/upload-artifact/pull/511/files

Author: HaoZeke

.github/workflows/build_wheels.yml

@@ -66,7 +66,7 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Build wheels
         uses: pypa/[email protected]
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v3
         with:
           path: ./wheelhouse/*.whl
 
@@ -86,7 +86,7 @@ jobs:
         shell: bash -l {0}
         run: pipx run build --sdist
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v3
         with:
           path: dist/*.tar.gz
 
@@ -103,7 +103,7 @@ jobs:
     # alternatively, to publish when a GitHub Release is created, use the following rule:
     # if: github.event_name == 'release' && github.event.action == 'published'
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v3
         with:
           # unpacks default artifact into dist/
           # if `name: artifact` is omitted, the action will create extra parent dir