refactor(update.sh): improve update script reliability and clarity

- Changed shebang to use env for better portability.
- Added error handling to ensure the script exits on failure.
- Included a check to confirm the current branch is 'main' before proceeding.
- Updated git commands to fetch and reset to origin/main, ensuring a clean state.
- Enhanced user feedback messages for clarity.

.gitea/workflows/deploy.yml

@@ -0,0 +1,21 @@
+name: Deploy to production
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Run deployment on production server
+        uses: appleboy/ssh-action@v1.0.3
+        with:
+          host: ${{ secrets.PROD_HOST }}
+          username: ${{ secrets.PROD_USER }}
+          key: ${{ secrets.PROD_SSH_KEY }}
+          port: ${{ secrets.PROD_PORT }}
+          script: |
+            /home/tsschulz/actualize-yourpart.sh