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-GNUPG2-9486681
- https://snyk.io/vuln/SNYK-DEBIAN12-KRB5-1549480
- https://snyk.io/vuln/SNYK-DEBIAN12-KRB5-6277421
- https://snyk.io/vuln/SNYK-DEBIAN12-KRB5-8679228

Dockerfile

@@ -1,5 +1,5 @@
 # Use an official Python runtime as a parent image
-FROM python:3.9-slim
+FROM python:3.13.3-slim
 
 # Create a working directory
 WORKDIR /app