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-GLIBC-1547196
- https://snyk.io/vuln/SNYK-DEBIAN12-GLIBC-1547196
- https://snyk.io/vuln/SNYK-DEBIAN12-TAR-1560620
- https://snyk.io/vuln/SNYK-DEBIAN12-PERL-5489184

Dockerfile

@@ -1,6 +1,6 @@
 # Based on recommendations from
 # https://snyk.io/blog/best-practices-containerizing-python-docker/
-FROM python:3.12-slim as build
+FROM python:3.14.0a3-slim as build
 
 WORKDIR /app
 
@@ -17,7 +17,7 @@ COPY . .
 RUN --mount=source=.git,target=.git,type=bind
 RUN pip install .
 
-FROM python:3.12-slim
+FROM python:3.14.0a3-slim
 WORKDIR /app
 COPY --from=build /app/venv /app/venv
 ENV PATH="/app/venv/bin:$PATH"