Update merge process in GitHub workflow (#164)

The merge operation from 'dev' to 'main' has been refactored to use the
'merge-fast-forward-action'. This change simplifies the GitHub workflow
by replacing the manual git commands with a dedicated action. In
addition, custom success and failure messages have been provided for
better visibility of merge status.

.github/workflows/merge-main.yaml

@@ -25,14 +25,11 @@ jobs:
           git config user.name ${{ github.actor }}
 
       - name: Merge dev -> main
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-        run: |
-          git status
-          git fetch
-          git checkout dev
-          git pull
-          git checkout main
-          git rebase dev
-          git push origin main
-          git status
+        uses: pascalgn/merge-fast-forward-action@v1.3.0
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SUCCESS_MESSAGE: "Release merged successfully via fast-forward"
+          FAILURE_MESSAGE: "Failed to merge release via fast-forward"
+          UPDATE_STATUS: "true"
+          PRODUCTION_BRANCH: "main"
+          STAGING_BRANCH: "dev"