[update] Ability to set a maximum version for specific variants

.github/workflows/build.yml

@@ -449,6 +449,19 @@ jobs:
         asset_name: SHA2-512SUMS
         asset_content_type: text/plain
 
+    - name: Make Update spec
+      run: |
+        echo "# This file is used for regulating self-update" >> _update_spec
+    - name: Upload update spec
+      uses: actions/upload-release-asset@v1
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      with:
+        upload_url: ${{ needs.create_release.outputs.upload_url }}
+        asset_path: ./_update_spec
+        asset_name: _update_spec
+        asset_content_type: text/plain
+
     - name: Finalize release
       env:
         GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}