Downgrade actions/download-artifact to v3

Author: zfergus

.github/workflows/pypi.yml

@@ -75,7 +75,7 @@ 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@v4.1.7
+      - uses: actions/download-artifact@v3
         with:
           # unpacks default artifact into dist/
           # if `name: artifact` is omitted, the action will create extra parent dir