fix: modules/openapi-generator/src/main/resources/python-flask/Docker…

…file.mustache to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE319-EXPAT-6241037
- https://snyk.io/vuln/SNYK-ALPINE319-EXPAT-6241038

modules/openapi-generator/src/main/resources/python-flask/Dockerfile.mustache

@@ -2,7 +2,7 @@
 FROM python:2-alpine
 {{/supportPython2}}
 {{^supportPython2}}
-FROM python:3-alpine
+FROM python:3.13.0a4-alpine
 {{/supportPython2}}
 
 RUN mkdir -p /usr/src/app