fix(ci): get proper release url (hopefully)

Author: ptsouchlos

.github/workflows/release.yml

@@ -50,12 +50,19 @@ jobs:
         run: |
           just doc
           just package out
+
+      - name: Get release
+        id: get_release
+        uses: bruceadams/get-release@v1.3.2
+        env:
+          GITHUB_TOKEN: ${{ github.token }}
+
       - name: Upload manual
         uses: actions/upload-release-asset@v1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
-          upload_url: ${{ github.event.release.upload_url }}
+          upload_url: ${{ steps.get_release.outputs.upload_url }}
           asset_path: docs/manual.pdf
           asset_name: "${PKG_NAME}-${PKG_VERSION}-manual.pdf"
           asset_content_type: application/pdf