[Snyk] Security upgrade python from slim-bullseye to 3.13.0a2-slim (#75)

* fix: backend-py/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN11-DB53-2825168
- https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-521063
- https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-521063
- https://snyk.io/vuln/SNYK-DEBIAN11-SQLITE3-6139925
- https://snyk.io/vuln/SNYK-DEBIAN11-ZLIB-6008961

* Update python builder to bookworm

* Upgrade base to bookworm

---------

Co-authored-by: snyk-bot <snyk-bot@snyk.io>
Co-authored-by: Derek Roberts <derek.roberts@gmail.com>

backend-py/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:bullseye AS build
+FROM python:bookworm AS build
 
 # Disable cache dir, disable upgrade message, create .venv in project dir
 ARG PIP_NO_CACHE_DIR=off \
@@ -8,11 +8,11 @@ ARG PIP_NO_CACHE_DIR=off \
 # Install poetry, then dependencies
 WORKDIR /app
 COPY pyproject.toml poetry.lock ./
-RUN pip install poetry==1.6.1 && \
-    poetry install --no-root -vvv --without dev --sync
+RUN pip install poetry==1.6.1
+RUN poetry install --no-root -vvv --without dev --sync
 
 # Deploy
-FROM python:slim-bullseye AS deploy
+FROM python:slim-bookworm AS deploy
 
 # Output to stdout/stderr, don't create .pyc files, etc.
 ENV PYTHONUNBUFFERED=1 \