fix: Use official Python image for backup container

- Change from dockerhub.wace.me/python:3.10-slim.linux to python:3.10-slim
- Fix Docker image not found error

Dockerfile.backup

@@ -1,5 +1,5 @@
 # Use an official Python runtime as a parent image
-FROM dockerhub.wace.me/python:3.10-slim.linux
+FROM python:3.10-slim
 
 # Set environment variables
 ENV PYTHONDONTWRITEBYTECODE=1