workflow: use merge instead of rebase

.gitea/workflows/update-flake.yaml

@@ -16,10 +16,18 @@ jobs:
           fetch-depth: 0
           ref: flake-updates
 
-      - name: Fetch latest changes and rebase
+      - name: Git config
+        shell: bash
         run: |
-          git fetch origin
-          git rebase origin/main
+          git config user.name "Gitea Actions"
+          git config user.email "actions@gitea.local"
+
+      - name: Merge main branch
+        run: |
+          git merge --squash origin/main
+          # solve merge conflict by taking flake.lock from main
+          git checkout origin/main -- flake.lock
+          git commit -m "Merge main branch squashed $(date -I)"
 
       - name: Set up Nix
         uses: cachix/install-nix-action@v31
@@ -30,12 +38,10 @@ jobs:
       - name: Commit and push changes
         shell: bash
         run: |
-          git config user.name "Gitea Actions"
-          git config user.email "actions@gitea.local"
           git add flake.lock
           if git diff --cached --quiet; then
             echo "No changes to commit."
           else
             git commit -m "Update flake.lock $(date -I)"
-            git push --force-with-lease origin flake-updates
+            git push origin flake-updates
           fi