ci: change auto-merge strategy to merge instead of squash

Author: nmccready

.github/workflows/dependabot-auto-merge.yml

@@ -23,8 +23,8 @@ jobs:
           PR_URL: ${{ github.event.pull_request.html_url }}
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Enable auto-merge (squash)
-        run: gh pr merge --squash --auto "$PR_URL"
+      - name: Enable auto-merge
+        run: gh pr merge --merge --auto "$PR_URL"
         env:
           PR_URL: ${{ github.event.pull_request.html_url }}
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}