ci: add automatic rebase of v2 on main after push to main

.github/workflows/rebase-v2-on-main.yml

@@ -0,0 +1,57 @@
+on:
+  push:
+    branches:
+      - main
+
+  workflow_dispatch:
+
+env:
+  VSTEST_CONNECTION_TIMEOUT: 180
+  DOTNET_SKIP_FIRST_TIME_EXPERIENCE: 1
+  DOTNET_NOLOGO: true
+  DOTNET_SYSTEM_CONSOLE_ALLOW_ANSI_COLOR_REDIRECTION: 1
+  TERM: xterm
+
+jobs:
+  rebase:
+    name: 🎁 Rebase V2 on Main
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: 🛒 Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          token: ${{ secrets.BUNIT_BOT_TOKEN }}
+
+      - name: ⚙️ Import GPG key
+        id: import_gpg
+        uses: crazy-max/ghaction-import-gpg@v6
+        with:
+          gpg_private_key: ${{ secrets.BUNIT_BOT_GPG_PRIVATE_KEY }}
+          passphrase: ${{ secrets.BUNIT_BOT_GPG_KEY_PASSPHRASE }}
+
+      - name: ⚙️ Setup CI GIT
+        run: |
+          git config user.name "${{ steps.import_gpg.outputs.name }}"
+          git config user.email ${{ steps.import_gpg.outputs.email }}
+          git config --global user.signingkey ${{ steps.import_gpg.outputs.keyid }}
+          git config --global commit.gpgsign true
+
+      - name: ⏩ Merge stable with main, push to origin
+        id: rebaseV2
+        continue-on-error: true
+        run: |
+          git checkout v2
+          git git rebase origin/main
+          git push origin v2
+
+      - name: ⏭ Create pull request from main to v2 when direct rebase fails
+        if: steps.rebaseV2.outcome == 'failure'
+        uses: thomaseizinger/create-pull-request@1.3.1
+        env:
+          GITHUB_TOKEN: ${{ secrets.BUNIT_BOT_TOKEN }}
+        with:
+          head: main
+          base: v2
+          title: Rebase v2 on main