ci: automate publishing (#17086)

* ci: automate publishing

Signed-off-by: David Karlsson <david.karlsson@docker.com>
Co-authored-by: CrazyMax <github@crazymax.dev>

---------

Signed-off-by: David Karlsson <david.karlsson@docker.com>
Co-authored-by: CrazyMax <github@crazymax.dev>

.github/workflows/merge.yml

@@ -0,0 +1,24 @@
+name: merge
+
+# open or update publishing PR when there is a push to main
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+
+jobs:
+  main-to-published:
+    runs-on: ubuntu-22.04
+    if: github.repository_owner == 'docker'
+    steps:
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@5b4a9f6a9e2af26e5f02351490b90d01eb8ec1e5
+        with:
+          delete-branch: false
+          branch: published
+          commit-message: &msg publish updates from main
+          labels: area/release
+          title: *msg
+          body: |
+            Automated pull request for publishing docs updates.