fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN12-ZLIB-6008963
- https://snyk.io/vuln/SNYK-DEBIAN12-SHADOW-5423923
- https://snyk.io/vuln/SNYK-DEBIAN12-SHADOW-5879156
- https://snyk.io/vuln/SNYK-DEBIAN12-SQLITE3-2407042
- https://snyk.io/vuln/SNYK-DEBIAN12-SQLITE3-6139924

Dockerfile

@@ -3,7 +3,7 @@ COPY requirements.txt .
 
 RUN pip install --user -r requirements.txt 
 
-FROM python:3.9-slim
+FROM python:3.13.0rc2-slim
 WORKDIR /app
 COPY --from=builder /root/.local/* /app/.local/
 COPY chksftp.py .