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-APT-1541449
- https://snyk.io/vuln/SNYK-DEBIAN12-APT-1541449
- https://snyk.io/vuln/SNYK-DEBIAN12-COREUTILS-1543939
- https://snyk.io/vuln/SNYK-DEBIAN12-COREUTILS-1543947

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3-slim AS builder
+FROM python:3.13.0b4-slim AS builder
 ADD . /app
 WORKDIR /app