Add automation to create a release branch

.ci/scripts/create_release_branch.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+set -eu -o pipefail
+
+BRANCH="$(git branch --show-current)"
+
+if ! [[ "${BRANCH}" = "develop" ]]
+then
+  echo ERROR: This is not the main branch!
+  exit 1
+fi
+
+NEW_VERSION="$(bump-my-version show new_version --increment release | sed -Ene 's/^([[:digit:]]+\.[[:digit:]]+)\.[[:digit:]]+$/\1/p')"
+
+if [[ -z "${NEW_VERSION}" ]]
+then
+  echo ERROR: Could not parse new version.
+  exit 1
+fi
+
+NEW_BRANCH="RELEASE-${NEW_VERSION}"
+
+git branch "${NEW_BRANCH}"
+
+bump-my-version bump minor --commit --message $'Bump version to {new_version}' --allow-dirty
+
+git push origin "${NEW_BRANCH}"
+
+if [ "${GITHUB_ENV:-}" ]
+then
+  echo "NEW_BRANCH=${NEW_BRANCH}" >> "${GITHUB_ENV}"
+fi

.github/workflows/release_branch.yml

@@ -0,0 +1,46 @@
+---
+name: "Create Release Branch"
+on:
+  workflow_dispatch:
+
+jobs:
+  create-release-branch:
+    runs-on: "ubuntu-latest"
+    steps:
+      - uses: "actions/checkout@v4"
+      - name: "Set up Python"
+        uses: "actions/setup-python@v5"
+        with:
+          python-version: "3.13"
+      - name: "Setup git"
+        run: |
+          git config user.name pulpbot
+          git config user.email [email protected]
+      - name: "Install python dependencies"
+        run: |
+          pip install bump-my-version~=0.29.0
+      - name: "Create Release Branch"
+        run: |
+          .ci/scripts/create_release_branch.sh
+      - name: "Create Pull Request"
+        uses: "peter-evans/create-pull-request@v7"
+        with:
+          token: "${{ secrets.RELEASE_TOKEN }}"
+          title: "Bump dev-version"
+          body: ""
+          branch: "bump_version"
+          delete-branch: true
+      - name: "Add Backport Label for new Branch"
+        uses: "actions/github-script@v7"
+        with:
+          script: |
+            const { NEW_BRANCH } = process.env;
+            const labelName = "backport-" + NEW_BRANCH;
+
+            await github.rest.issues.createLabel({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              name: labelName,
+              color: "C8780A",
+            });
+...