Update merge-maintained-branch workflow with ort strategy

Author: ondrejmirtes

.github/workflows/merge-maintained-branch.yml

@@ -20,10 +20,13 @@ jobs:
 
       - name: "Checkout"
         uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
-      - name: "Merge branch"
-        uses: everlytic/branch-merge@c4a244dc23143f824ae6c022a10732566cb8e973 # 1.1.5
         with:
-          github_token: "${{ secrets.PHPSTAN_BOT_TOKEN }}"
-          source_ref: ${{ github.ref }}
-          target_branch: '2.2.x'
-          commit_message_template: 'Merge branch {source_ref} into {target_branch}'
+          fetch-depth: 0
+          ref: '2.2.x'
+          token: "${{ secrets.PHPSTAN_BOT_TOKEN }}"
+      - name: "Merge branch"
+        run: |
+          git config user.name "phpstan-bot"
+          git config user.email "bot@phpstan.org"
+          git merge --strategy=ort origin/${{ github.ref_name }} -m "Merge branch ${{ github.ref_name }} into 2.2.x"
+          git push