fix: samples/server/petstore/python-fastapi/Dockerfile to reduce vuln…

…erabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN12-GLIBC-5927132
- https://snyk.io/vuln/SNYK-DEBIAN12-GLIBC-5927132
- https://snyk.io/vuln/SNYK-DEBIAN12-GLIBC-5927132
- https://snyk.io/vuln/SNYK-DEBIAN12-GLIBC-5927132
- https://snyk.io/vuln/SNYK-DEBIAN12-NGHTTP2-5953379

samples/server/petstore/python-fastapi/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.7 AS builder
+FROM python:3.13.0rc2 AS builder
 
 WORKDIR /usr/src/app
 
@@ -11,7 +11,7 @@ COPY . .
 RUN pip install --no-cache-dir .
 
 
-FROM python:3.7 AS test_runner
+FROM python:3.13.0rc2 AS test_runner
 WORKDIR /tmp
 COPY --from=builder /venv /venv
 COPY --from=builder /usr/src/app/tests tests
@@ -24,7 +24,7 @@ RUN pip install pytest
 RUN pytest tests
 
 
-FROM python:3.7 AS service
+FROM python:3.13.0rc2 AS service
 WORKDIR /root/app/site-packages
 COPY --from=test_runner /venv /venv
 ENV PATH=/venv/bin:$PATH