upgrade python minor, pin pipenv and poetry, pull out python3-dev and postgres client

Dockerfile

@@ -1,15 +1,17 @@
-FROM python:3.11-slim
+FROM python:3.11.6-slim
 
 WORKDIR /app
+
+# pulled out:
+# python3-dev \
+# postgresql-client \
 RUN set -xe \
-  && pip install pipenv poetry==1.2.2 \
+  && pip install pipenv==2023.10.3 poetry==1.6.1 \
   && apt-get update -q \
   && apt-get install -y -q \
         gcc \
-        python3-dev \
         libssl-dev \
         curl \
-        postgresql-client \
         git-core \
         gunicorn3