CI: Fix PyPI release action

Need to handle the fact that with multiple artificats, they're unpacked
into a directory for each. Therefore we need steps to consolidate into
the dist/ directory.

.github/workflows/release.yml

@@ -34,8 +34,9 @@ jobs:
     - name: Save built packages as artifact
       uses: actions/upload-artifact@v2
       with:
-        name: ${{ runner.os }}-${{ steps.setup.outputs.python-version }}
+        name: packages-${{ runner.os }}-${{ steps.setup.outputs.python-version }}
         path: dist/
+        if-no-files-found: error
         retention-days: 5
 
   publish:
@@ -48,8 +49,11 @@ jobs:
     steps:
     - name: Download packages
       uses: actions/download-artifact@v2
-      with:
-        path: ./dist
+
+    - name: Consolidate packages for upload
+      run: |
+        mkdir dist
+        cp packages-*/* dist/
 
     - name: Publish Package
       uses: pypa/gh-action-pypi-publish@v1.5.0