fix: vote/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-KRB5-1549480
- https://snyk.io/vuln/SNYK-DEBIAN12-KRB5-6277411
- https://snyk.io/vuln/SNYK-DEBIAN12-SHADOW-8551160
- https://snyk.io/vuln/SNYK-DEBIAN12-SHADOW-8551160

vote/Dockerfile

@@ -1,5 +1,5 @@
 # Using official python runtime base image
-FROM python:3.9-slim
+FROM python:3.14.0a1-slim
 
 # add curl for healthcheck
 RUN apt-get update \