add artifact upload step to allow examining the build result

Author: mattip

.github/workflows/build.yml

@@ -91,6 +91,10 @@ jobs:
           cp $(cygpath $OPENBLAS_ROOT)/$BITS/bin/*.dll .
           ./test_dyn.exe
 
+      - uses: actions/upload-artifact@v3
+        with:
+          path: builds/openblas*.zip
+
       - name: Upload
         env:
          OPENBLAS_LIBS_STAGING_UPLOAD_TOKEN: ${{ secrets.MULTIBUILD_WHEELS_STAGING_ACCESS }}

.github/workflows/multibuild.yml

@@ -100,6 +100,11 @@ jobs:
         clean_code $REPO_DIR $OPENBLAS_COMMIT
         echo "------ BUILD LIB --------"
         build_lib "$PLAT" "$INTERFACE64"
+
+    - uses: actions/upload-artifact@v3
+      with:
+        path: libs/openblas*.tar.gz
+
     - name: Upload tarballs
       run: |
         set -ex