Upload vsix to workflow artifacts

Author: jneira

.github/workflows/build.yml

@@ -24,7 +24,12 @@ jobs:
         uses: HaaLeo/publish-vscode-extension@v0
         with:
           pat: ${{ secrets.OPEN_VSX_TOKEN }}
-      - name: Upload extension vsix
+      - name: Upload extension vsix to workflow artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: haskell-${{ github.event.release.tag_name }}.vsix
+          path: ${{ steps.publishToVSMarketplace.outputs.vsixPath }}
+      - name: Upload extension vsix to release assets
         uses: actions/[email protected]
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}