distro build: push release branches

build/azure-pipelines/distro-build.yml

@@ -30,7 +30,13 @@ steps:
 
     git remote add distro "https://github.com/$VSCODE_MIXIN_REPO.git"
     git fetch distro
-    git push distro origin/master:refs/heads/master
+
+    # Push master branch into master and oss/master
+    git push distro origin/master:refs/heads/master origin/master:refs/heads/oss/master
+
+    # Push every release branch into oss/release
+    git for-each-ref --format="%(refname:short)" refs/remotes/origin/release/* | sed 's/^origin\/\(.*\)$/\0:refs\/heads\/oss\/\1/' | xargs git push
+
     git merge $(node -p "require('./package.json').distro")
 
   displayName: Sync & Merge Distro
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